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This experimental research variable is the one that is manipulated by the researcher; it is sometimes referred to as the "input variable."
Independent variable
In experimental research, the hypothesis can usually be stated: changes in the ________ will be caused by changes in the ________.
Dependent variable; independent variable
Referred to as the "outcome variable," it is hypothesized to change as a result of particular manipulations of the input variable in experimental research.
Dependent variable
In correlational research, independent variables are often termed ________ to differentiate them from manipulatable variables, and dependent variables are referred to as ________.
Predictor; criterion
What term is used to denote the values a research variable, most often the independent variable, could take (e.g., placebo only, placebo + treatment, treatment only)?
Levels (of a variable)
In what type of research design are all levels of one independent variable combined with all levels of another independent variable?
Factorial design (if one IV has 3 levels and the other has 2, it would be called a 3 x 2 factorial design)
A study is said to have ________ validity when a causal relationship is determined to exist between the independent and dependent variables.
Internal
True or False: A study in which no significant effect of the independent variable is found will always have no internal validity?
False- it will have internal validity if the conclusion is that the IV has no causal effect on the DV
Poor internal validity in a study is the result of numerous possible extraneous variables, typically called ________ variables, that might explain the change in the dependent variable.
Confound
What is the single best way for a researcher to ensure internal validity when conducting an experiment?
Treat all "levels" of the IV with equivalence (equally) in every respect, except for their IV status
Regarding confound variables effecting change in the DV, ________ is a result of biological or psychological change in the research subjects; ________ is a result of one's prior experience with a test; ________ might occur when there have been changes in the measuring instrument (e.g., psychologists gets better at diagnosing); ________ is caused by pre-existing factors in the research subjects (e.g., higher IQs); and ________ is the result of people who drop-out of one research group systematically differ from those who stay in the study.
Maturation; testing; instrumentation; selection; differential mortality
This term is used to describe the tendency for a test subject who initially produced extreme scores on a measure to score closer to the mean on subsequent testings; it has an effect on internal validity when extreme scorers are used as research subjects.
Statistical regression
Changes in the behavior of test subjects (DV) that is more a function of the expectations of the experimenter as opposed to the independent variables is referred to as what?
The Rosenthal effect
This is likely the best technique for ensuring internal validity, as it distributes all extraneous subject characteristics equally to all research groups, thereby reducing the likelihood of confounded results.
Random assignment (or randomization)
Random ________ occurs after study subjects have already been selected to participate and refers to the equal probability of being assigned to a group, whereas random ________ occurs prior to starting the study and refers to a method whereby all members of a population have an equal chance of being chosen to participate in a study.
Assignment; selection (or sampling)
Experimenters are interested in measuring the effect that different treatment modalities (IV) have on relapse rates for alcoholics; however, there is concern that the duration of each subject's alcohol use may confound the results. The researchers decide to split the subjects based on their duration of use, then randomly assign them to treatment groups. This is an example of what technique to increase internal validity?
Matching
What technique for ensuring internal validity involves essentially making the confound variable another independent variable, allowing the researcher to separate the effects of each variable?
Blocking
This statistical strategy for increasing internal validity involves adjusting DV scores after the data has been analyzed so that subjects statuses are equalized on 1 or more variables; it is similar to matching, only it is performed post-hoc.
Analysis of Covariance (ANCOVA)
If the results of a study can be generalized to other settings and situations, it would be said to have high ________.
External validity
When the effects of a given treatment are not generalizable to other members of the target population, it can be said that there is an interaction between ________ and ________.
Selection; treatment
When the result of a study performed in the 1920s does not apply to the population in 2010, there is an interaction between ________ and ________.
History; treatment
An interaction between ________ and ________ occurs when the results of a study where pretests were used does not generalize to cases in which pretests were not used.
Testing; treatment
What is the term used to describe the phenomenon where research participants form an interpretation of the experiment's purpose and, consequently, unconsciously change their behavior or responses accordingly?
Demand characteristics
A research subject who behaves differently merely due to the fact that they are aware of their participation in an experiment exemplifies what threat to external validity?
The Hawthorne Effect
In studies where the same subjects are exposed to more than 1 treatment (called repeated measures design), there is a risk that external validity will be decreased as a result of the influence of the multiple treatments, thereby reducing generalizability. This is referred to as what?
Order effects, carryover effects, or multiple treatment interference
A good way of increasing external validity, ________ ensures that all members of a population have an equal chance of being selected to participate in the research, and thereby produces results that accurately represent the whole population (it is generalizable).
Random sampling (or selection)
This procedure involves taking a random sample from each of numerous subgroups of the total target population, thus ensuring proportionate representation of the defined population subgroups in the study.
Stratified random sampling
While a threat to internal validity, ________ research increases external validity by observing subjects' behavior in a real-life setting.
Naturalistic
In contrast to naturalistic research, which has high external and low internal validity, ________ research tends to have higher internal and lower external validity.
Analogue (research performed in more laboratory-like setting)
A ________ study involves the subjects lacking awareness of the purpose of the experiment and the treatment they have been assigned to; in a ________ study, both the subjects and the experimenters lack awareness of the group subjects have been assigned to.
Single-blind; double-blind
One way of controlling for order effects is to administer treatment to groups of subjects in a different order, which is referred to as what?
Counterbalancing
What counterbalancing technique orders the administration of treatment so that each appears only once in every position?
Latin square design
The defining feature of a ________ experiment is that subjects are randomly assigned to different groups; in contrast, ________ experiments are performed when it is impossible to randomly assign subjects to groups (e.g., intact groups of subjects).
True; quasi
In this type of research, variables of interest are not manipulated, there is no internal validity, results are typically used for the purposes of prediction, and associative rather than causative relationships are discussed.
Correlational research
What type of research is used to address variables as a function of time, such as aging or maturation?
Developmental research
The 3 types of developmental research are ________ (same people studied over a long period of time), ________ (different groups of subjects who are divided by age are assessed at the same time), and ________ (representative samples of different age groups are assessed on 2 or more occasions).
Longitudinal; cross-sectional; cross-sequential (which is a combination of the first 2)
In cross-sectional research, what term describes the observed differences between different age groups that are more a function of experience than age?
Cohort (or intergenerational) effect
Longitudinal research tends to ________ true age-related change (due to drop-out of less-abled subjects and practice effects), while cross-sectional tends to ________ true age-related change (due to cohort effects).
Underestimate; overestimate
This type of research design consists of taking multiple measurements over time in order to assess the effects of an independent variable; the series of measurements on the dependent variable is interrupted by administration of the treatment.
Interrupted time-series design
In ________ designs, which work well for research on behavior modification, one subject serves as his/her own control; behavior (dependent variable) is analyzed numerous times during a baseline phase where there is no treatment, then again during a treatment phase (independent variable).
Single-subject
Of the 3 single-subject designs, a/an ________ involves collecting data from a single baseline phase and a single treatment phase; in a/an ________, data is collected after the treatment phase has stopped and, if the behavior returns, there is a higher chance the change was due to treatment; and ________ involves applying treatment sequentially and measuring the DV after each application, rather than removing treatment (this is used primarily when removing treatment would be unethical).
AB design; reversal (withdrawal) design; multiple baseline design
What 2 reversal designs involve (1) collecting data at a third non-treatment/baseline phase and (2) re-administering treatment for a second time, collecting data, and comparing the results to the first treatment phase?
(1) ABA design; (2) ABAB design
In ________ research, theories are derived from the gathered data rather than developed prior to the experiment; methods for collecting data include surveys (e.g., personal interviews, phone/mail surveys), case studies, and protocol analysis (collecting and analyzing word-for-word reports from subjects).
Qualitative, or descriptive
The two types of statistical methods are ________ statistics, which are used to quantitatively describe the main features data collected from a sample, and ________ statistics, which are used to make inferences regarding some unknown aspect of a population based on sample data.
Descriptive; inferential
Identify which of the 4 scales of measurement would be used for each of the following variables: (1) IQ scores or scores on most standardized tests, (2) diagnostic category, (3) the length of time (in minutes) it takes to complete a task, and (4) rankings of one's preferences of listed therapist characteristics.
(1) Interval, (2) nominal, (3) ratio, and (4) ordinal
What is the only difference between interval and ratio scales of measurement?
Ratio variables have an absolute zero point (e.g., distance, height, weight, time); interval variables have no absolute zero, so negative values can be used, and ratios are arbitrary- values cannot be multiplied or divided (e.g., IQ scores, temperature)
What descriptive statistic would be used if a researcher was interested in simply showing a summarized grouping of data she has collected, organized by the number of cases that fall within a given range or category?
Frequency distribution, which are often displayed on a bar graph (histogram), table graph, or polygon
A bell-curve exemplifies a ________ distribution, which is symmetrical due to half of the scores falling above the mean and half falling below the mean; a ________ distribution occurs when the majority of scores fall on the high end of the scale (e.g., test was too easy), leaving a long tail on the left; a ________ distribution occurs when most scores fall on the low end of the scale (e.g., test was too difficult), leaving a long tail on the right.
Normal; negatively; positively (hint: "the tail tells the tale," so whatever end the tail is on determines the labeling)
What are the 3 most common measures of central tendency?
Mean, median, and mode
The ________ is determined by dividing the sum of all values by the number of cases/scores (or N), providing the most useful measure of central tendency (MCT) for normal distributions; the ________ is the middle value when data is ordered from lowest to highest, making it less sensitive to extreme scores than the prior MCT and thus more useful with skewed distributions; the ________ is the most frequent value in a data set (can have more than one).
Mean; median; mode
How is the median calculated when there are an even number of cases in the data set?
Take the mean of the 2 middle values
In a negatively skewed distribution, ________ > ________ > ________; in a positively skewed distribution ________ > ________ > ________.
Mode > median > mean; mean > median > mode (hint: mean is always closer to the tail)
What are the 3 most common measures of variability (or dispersion)?
Range, variance, and standard deviation
The ________ is determined by simply subtracting the lowest score for the highest score in a data set, which limits it's usefulness; the ________ is used by many statistical tests in their formulas and it measures a distribution's variability; the ________, in simple terms, shows how much variation there is from the mean.
Range; variance; standard deviation
The ________ is the square of the ________, which means the ________ is the square root of the ________.
Variance; standard deviation; standard deviation; variance
This type of transformed score measures the amount of standard deviations a raw score is from the mean; once all raw scores have been converted, the distribution has a mean of 0 and a standard deviation of 1, permitting comparisons across different measures/tests.
Z-score
True or False: When raw scores are transformed into z-scores, the shape of the distribution stays the same?
True- when score transformation does not change distribution shape, it is called "linear transformation"
What transformed score has a mean of 50 and a standard deviation of 10?
T-score
This type of transformed score divides a distribution into 9 equal intervals with a mean of 5 and a standard deviation of 2.
Stanine scores (shortened form of STAndard NINE)
Expressed as the percentage of individuals in a standardized group scoring below an individual's raw score, ________ are often helpful when providing feedback from intelligence and psychological tests.
Percentile ranks
Percentile ranks will always have a ________ distribution, meaning that within a given range of percentile ranks, there will always be the same number of scores.
Flat (or rectangular)
True or False: When raw scores are transformed into percentile ranks, the shape of the distribution stays the same?
False- when score transformation changes distribution shape, it is called "nonlinear transformation"
In a normal distribution, what percentage of scores falls within -1 and +1 standard deviations of the mean? Within -2 and +2? Within -3 and +3?
Approximately 68%, 95%, and 99% or scores fall within -1 and +1, -2 and +2, and -3 and +3 standard deviations, respectively
True or False: When raw scores are transformed into z-scores, the shape of the distribution stays the same?
True- when score transformation does not change distribution shape, it is called "linear transformation"
In a normal distribution, a z-score of +1.0 is equal to a percentile rank of ________ and is therefore the cutoff point for the top ________.
84; 16% (the same is true for the converse- a z-score of -1.0 has a percentile rank of 16 and is therefore the cutoff for the bottom 16%)
In a normal distribution, a z-score of ________ is equal to a percentile rank of 98 and is therefore the cutoff point for the top ________.
+2.0; 2% (the same is true for the converse- a z-score of -2.0 has a percentile rank of 2 and is therefore the cutoff for the bottom 2%)
The formula for a ________ involves subtracting the sample mean from the obtained raw score, then dividing that value by the standard deviation.
Z-score
This term refers to the inaccuracies that are a result of observing a sample rather than the whole population when using inferential statistical methods; it is the difference between the statistic (sample value) and the parameter (population value).
Sampling error (or "error of the mean")
The extent to which a sample mean can be expected to deviate from its corresponding population mean is referred to as the ________ and is calculated using the formula: ________.
Standard Error of the Mean (SEM); standard deviation/square root of N (N = sample size)
When calculating the standard error of the mean, what occurs as the sample size (N) becomes larger?
Error becomes smaller (there is an inverse relationship between sample size and SEM)
The standard error of the mean is ________ proportional to the standard deviation and ________ proportional to the sample size.
Directly; inversely
The difference between ________ hypothesis testing and ________ hypothesis testing is that the former states the hypothesis in theoretical terms while the latter states the hypothesis in terms that are quantitatively testable.
Research; statistical
The hypothesis that the independent variable will have no effect on the dependent variable is called the ________ hypothesis, while the ________ hypothesis hypothesizes the independent variable will have a significant effect on the dependent variable.
Null (H1: u1=u2); alternative (H1: u1/=u2)
The hypothesis that the implementation of a certain smoking cessation program will significantly reduce smoking exemplifies a ________ hypothesis, while the hypothesis that a new therapy approach will change the mean test scores of patients with schizophrenia exemplifies a ________ hypothesis.
One-tailed (the direction of the change is hypothesized); two-tailed (no direction of change is hypothesized)
A ________ occurs when the null hypothesis is rejected when it is true- basically, the researcher finds a significant difference when in the population no difference exists, creating a "false-positive." The ________ level refers to the probability of making such an error and is usually set at the .01 or .05 level, which means a researcher would reject the null hypothesis if the test indicates that there is a 1% or less or 5% or less chance of the null hypothesis being true.
Type I error; alpha (p value)
The probability at which a researcher rejects the null hypothesis as being true is called what?
The significance level, usually expressed "the results were significant (p < .01)"
On a graphical representation, when alpha level is changed from .05 to .01, the ________ region gets smaller and the ________ region gets larger.
Rejection (i.e., level at which null hypothesis is rejected); retention (i.e., level at which null hypothesis is retained)
A ________ occurs when the null hypothesis is not rejected when it is false- basically, the researcher finds no significant difference when in the population a difference does exist, creating a "false-negative." ________ is the probability of making such an error, while ________ refers to probability of not making such an error (or, the probability of rejecting the null when it is false).
Type II error; beta; power (refers to "sensitivity of a statistical test;" equal to 1-beta)
While the power of a statistical test is not known prior to a study and usually remains unknown, what are some ways a researcher can increase power?
Increase sample size, increase the pre-set alpha level, use a one-tailed (directional) test, increase the difference between levels of the independent variable
True or False: As the probability of making a Type I error increases, the probability of making a Type II error decreases, and vice-versa?
True- hence researchers must consider real-world consequences of making these errors when setting alpha
In research where the hypothesis is counter-intuitive and contradicts previous findings/theory, alpha should be set at ________ in order to reduce the chances of making a ________ error (remember "COLD FUSION"); however, alpha should be set at ________ in situations where making a ________ error might have devastating affects (e.g., research on new medicine to treat a life-threatening illness).
A lower value (.01); Type I error; a higher value (.05); Type II error
The ANOVA and the t-test are both examples of ________ tests, which are used only for data measured on ________ or ________ scales.
Parametric; interval; ratio
Parametric tests are based on the assumptions of ________ (dependent variable values are normally distributed in the population) and ________ (variance of all research groups is equal).
Normal distribution; homogeneity of variance
Designed to test hypotheses based on dependent variables measured on a ________ or ________ scale, ________ tests make no assumption of distribution ("distribution free"), which can decrease power, and include chi-square and Mann-Whitney U.
Nominal; ordinal; nonparametric
What assumption is shared by both parametric and nonparametric tests?
Random selection of subjects from the population
The probability of: rejecting a true null hypothesis = ________; retaining a false null hypothesis = ________; rejecting a false null hypothesis = ________.
Alpha; beta; power
In determining whether to reject or retain the null hypothesis, the statistical value is compared to a ________, which is dependent on 1) the pre-set alpha level and 2) the degrees of freedom for the statistical test used.
Critical value
This statistic is used to test whether there is a significant difference between 2 different means; it cannot be used to compare any more than 2 means.
t-Test (or Student's t-test)
A researcher wants to test the hypothesis that children in a low-SES school district receive less direct teacher contact than the national average for children. The researcher learns from a recent national survey that children receive an average of 6 hours per week of direct contact with their teacher; however, in her survey of children from a low-SES district, the average was 2.5 hours per week. What statistic would be used to determine if significance exists?
One sample t-test: used to compare the mean of a single sample to a known population mean (degrees of freedom = N - 1)
A researcher interested in studying the effects of a novel therapeutic approach to improve social function selects 100 people diagnosed with an anxiety disorder. Subjects are randomly assigned to either a group receiving the new treatment or a group receiving CBT, referred to as ________ samples. Data from a measure of social function is collected following 12 weeks of treatment. The researcher utilizes the ________ to test whether there is a significant difference between the groups.
Independent; t-test for independent samples (degrees of freedom = N - 2)
This test is used to compare the means of samples that are related to each other, such as in a pretest-posttest design where the same group of subjects is measured before and after treatment, then the means compared.
t-Test for correlated samples (degrees of freedom = N - 1, where N = pairs of scores)
A researcher interested in determining whether significant differences exist between 3 or more independent groups on a single independent variable would utilize a/an ________, yielding a/an ________ statistic that would indicate whether there was a difference in group means without telling where the differences lie; should the test yield significance, ________ tests can be used to specify the differences.
One-way ANOVA (can be used with 2 groups, but usually t-test is simpler); F-ratio; post-hoc
The ANOVA statistic (F-ratio) is based on a comparison of ________ variance and ________ variance, wherein the greater the former is over the latter, the greater the effect of the treatment (independent variable).
Between-group (or treatment); within-group (or error)
The first step in determining the F-ratio of a one-way ANOVA involves calculating the between-group and within-group ________, which is a measure of variability of a data set.
Sum of Squares
For a one-way ANOVA, degrees of freedom-between = k - 1 where k equals ________; degrees of freedom-within = N - k where N equals ________.
Number of groups; total number of subjects
Between-group variance is estimated by ________, which is calculated by dividing Sum of Squares-between by degrees of freedom-between; similarly, within-group variance is estimated by ________ , which is calculated by dividing Sum of Squares-within by degrees of freedom-within; the F-ratio is then calculated by dividing ________ by ________.
Mean Squares Between (MSB); Mean Squares Within (MSW); MSB; MSW
Should an F-ratio be higher than the critical value at a significance level of .05, how will the significance be indicated? How about at the .01 level?
A single asterisk indicates significance at the .05 level (p < .05), while 2 asterisks indicate significance at the .01 level (p* < .01)
Assuming a one-way ANOVA produces significance, ________ comparisons can help determine where the differences lie; however, when multiple comparisons are conducted, the probability that a/an ________ will occur increases, which is referred to as ________.
Post-hoc; Type I error; experiment-wise error rate
The most conservative post-hoc test is the ________ (protects against Type I error, which increases chance of Type II error); the ________ protects against Type I error when only pairwise comparisons are made.
Scheffe; Tukey
In a study where all of the subjects receive all of the levels of the independent variable (so they are not split into separate groups for comparison), or the study involves more than 2 matched groups, what statistic is used?
One way ANOVA for repeated measures
A/an ________ is used when a study involves more than 1 independent variable and 3 or more groups.
Factorial ANOVA
The benefit of using a factorial ANOVA over separate one-way ANOVAs is that a factorial ANOVA produces both ________ (effect of 1 independent variable by itself) and ________ (effects of an independent variable at the different levels of the other independent variables).
Main effects; interaction effects
In a factorial ANOVA, the differences between the ________ are examined to determine the main effects, while ________ are examined to determine interaction effects.
Marginal means; cell means
In graphical form, how is one able to tell if there is an interaction effect?
Interaction effects are indicated when lines cross
What parametric statistical procedure is used when a study involves 1 or more independent variables and 2 or more dependent variables?
Multivariate Analysis of Variance (MANOVA)
What test is used to assess whether observed frequencies differ significantly from what is expected under the null hypothesis when data is categorical (i.e., nominal)?
Chi-square
A chi-square that involves collecting categorical data from only 1 sample of subjects is called ________ chi-square test, while a ________ chi-square test involves adding another variable in addition to the one that gives rise to the classification categories.
Single-sample; multiple-sample
How are expected frequencies (fe) calculated for both a single-sample and a multiple-sample chi-square?
single-sample fe = N (# of subjects)/number of cells; multiple-sample fe = (column total x row total)/total N
True or False: In order to use chi-square, it is necessary that all observations be independent of each other?
True- "before-and-after" studies violate this rule and thus cannot use chi-square
Two tests used when data is rank-ordered (i.e., ordinal) include the ________, used when a study involves 2 independent groups, and the ________, used when correlated groups are compared; both can also be used when interval or ratio data does not meet the assumptions of parametric tests (i.e., normal distribution, homogeneity of variance), in which case data would be converted to ranks.
Mann-Whitney U; Wilcoxon Matched-Pairs Test
What test is used when data is rank-ordered and more than 2 groups are to be compared?
Kruskal-Wallis Test
The nonparametric alternative for a: one-way ANOVA is ________; t-test for independent samples is ________; t-test for correlated samples is ________.
Kruskal-Wallis Test; Mann-Whitney U; Wilcoxon Matched-Pairs Test
Typically ranging from -1.0 to +1.0, the ________ indicates the ________ (indicated by the absolute value) and ________ (indicated by the sign) of a relationship.
Correlation coefficient; magnitude; direction
This correlation coefficient is used to calculate the relationship 2 variables that are measured on an interval or ratio scale (e.g., relationship between IQ and scores on the SAT); it is the most commonly used correlation coefficient.
Pearson Product Moment Coefficient (Pearson r)
A correlation is referred to as ________ when Y is effected differently by different levels of X (e.g., children's anxiety level [X] and learning capacity [Y]: children learn best with moderate anxiety, and worse with low or high anxiety), in which case Pearson r cannot be used and the ________ coefficient would be used.
Curvilinear; eta
An assumption of the use of Pearson r is ________, which is when the dispersion of scores on a scattergram is equal; the term ________ refers there being more dispersion at some parts of the scattergram than others, which lowers the Pearson r coefficient.
Homoscedasticity; heteroscedasticity
This term refers to the squared correlation coefficient that indicates the percentage of variability in one measure that is accounted for by variability in the other measure; it is one way of interpreting the Pearson r.
Coefficient of determination
A variable that can have an infinite number of values between 2 given points is called ________ (e.g., income), while a ________ variable is a variable that categorizes data into 2 distinct groups (e.g., high/low, true/false, male/female).
Continuous; dichotomous
True or False: It is possible to transform continuous variables into dichotomous variables for use in a correlation coefficient?
True- the variable is then referred to as "artificially dichotomous," though it is not recommended to do this
Identify the correlation coefficient to use: X and Y = continuous (income x IQ); X = true dichotomy and Y = continuous (gender x income); X = artificial dichotomy and Y = continuous (income as "upper" or "lower" x IQ); X and Y = true dichotomy (a MMPI-2 question x gender); X and Y = artificial dichotomy (income as "upper" or "lower" x IQ as "high" or "low"); X and Y = ordinally ranked (relationship between scores given by 2 judges of a competition).
Pearson r; Point Biserial; Biserial; phi; Tetrachoric; Spearman's rho
An equation used to estimate the value of one variable based on the value of the other, when they are correlated, is referred to as what?
Regression equation
A researcher is interested in predicting the GRE scores of current undergraduate students based on their college GPA, which had previously been shown to be correlated. In this situation, GRE scores are the ________ variable while the ________ variable is GPA.
Criterion (dependent); predictor (independent)
A line that passes through as many dots as possible on a scattergram is called a regression line, or ________, which implies a linear relationship between 2 variables and is an assumption underlying regression.
Line of best fit
A ________ is used to assess the relationship between 2 or more predictor variables and a single criterion variable; the use of scores on more than 1 predictor to estimate scores on a criterion is referred to as ________.
Multiple correlation (Multiple R); multiple regression
The predictive power of the multiple regression equation is highest when predictor variables have ________ correlations with the criterion variable and ________ correlations with other, as this implies that each predictor variable is providing new information about the criterion; when predictors are highly correlated with each other, referred to as ________, combining them produces no substantially new information.
High; low; multicollinearity
True or False: Multiple R can be both positive and negative?
False- multiple R can never be negative, as the calculations do not allow for negative outcome
Is it ever possible for a multiple correlation coefficient (multiple R) to be lower than the highest simple correlation between an individual predictor and the criterion?
No- adding predictors will never decrease multiple R, though it may not increase it either
A researcher who has a large number of potential predictor variables wants to maximize predictive power by retaining the predictors that, combined, have a high multiple correlation with the criterion. What technique should be used?
Stepwise multiple regression
While multiple correlation indicates the magnitude of the relationship between multiple predictors and a single criterion variables, ________ is used when there are multiple predictor and multiple criterion variables.
Canonical correlation
What coefficient is used to assess 2 nominally scaled variables, each having more than 2 categories (e.g., political party x DSM diagnostic category)?
Contingency coefficient
What correlational technique involves predicting a categorical criterion/dependent variable by one or more continuous predictor/independent variables (e.g., membership in "high achievement" or "low achievement" group based on WAIS, Bender-Gestalt, and SAT scores)?
Discriminant function analysis, which is the statistical opposite of MANOVA
When would logistic regression, which is used to predict the criterion group one belongs to, be used in place of discriminant function analysis?
When the assumptions of normal distribution and homogeneity of variance are not met and/or when the predictor variables are not continuous (DFA predictors must be continuous)
What technique involves identifying different scores on a series of predictors that a person must score at or above to be predicted as successful on the criterion?
Multiple cutoff
Research results reveal that there is a relatively high correlation between 2 variables, though the researcher suspects there may be an additional variable contributing to this relationship. What technique might be used to statistically control for the effects of the other variable?
Partial correlation
What technique is used for testing and estimating causal relationships using a combination of statistical data and qualitative causal assumptions?
Structural equation modeling (SEM)
________ is used to verify directed (one-way) causal relationships (dependencies) between variables, while ________ can be used to verify both one-way and two-way causal flows; further, ________ can be used only in models that include observed variables (i.e., measurable), while ________ can be used in models that specify observed and latent variables (inferred as being measured).
Path analysis; LISREL; path analysis; LISREL
A researcher is not so much interested in determining the magnitude of relationship between quantitative variables (interval or ratio) as determining the course of change in the dependent variable over time. What correlational technique would be used in this case?
Trend analysis
The ________ describes the principle underlying the construction of a regression line, stating that a regression line is places at a location on the scattergram that results in the lowest possible sum of squared deviations of points from the line.
Least squares criterion
A ________ distribution is the entire set of cases a researcher is interested in, a ________ distribution is a set of scores obtained from the sample chosen from a population, and a ________ distribution (of any statistic) is the distribution of the statistic for all possible samples of a given size.
Population; sample; sampling
By choosing sample after sample of size N from a population, recording the value of the mean from each sample, then repeating this procedure thousands of times, what would be constructed?
Sampling distribution of means
According to the ________: (1) the shape of the sampling distribution of means approaches a normal shape as sample size increases, regardless of whether the population of distribution scores is normally distributed or not; and (2) the mean of the sampling distribution of means equals the population mean.
Central Limit Theorem
The standard deviation of the sampling distribution of means is equivalent to what?
The standard error of the mean
A statistical test is considered "________" when the Type I error rate is not significantly increased when assumptions of parametric tests are violated; basically, if they are violated, the results may still be accurate.
Robust
In a time-series analysis, the correlation between values obtained at different points in time is referred to as what?
Autocorrelation
This theorem shows how a conditional probability depends on its inverse (e.g., mammograms are 95% accurate, though a positive mammogram is likely inaccurate based on the relative rarity of breast cancer).
Bayes' Theorem (conditional probabilities and base rates)
A graduate student decides to analyze a group of independent studies that have a common conceptual basis. This is referred to as a/an ________, which yields a statistic called ________ that indicates the magnitude of an independent variable's effect.
Meta-analysis; effect size