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PSYC Test 1

Terms in this set (90)

Collecting information
When humans first realized that counting was a good idea, this became a useful skill for people to have:
outcomes
In early times, once numbers became part of the human language, the next step was to attach numbers to:
specific tools to answer specific questions
After the first set of data having to do with populations was collected during the 17th century scientists needed to develop:
true
Most of the basic statistical procedures were first developed and used in other fields and used to study human behavior much later.
true
The past 100 years has seen numerous examples of new ways to use old ideas.
SPSS
One of the most used statistical programs that has opened up the use of sophisticated techniques to those who want to explore is:
The same
Today, statisticians in many different professional areas find themselves using ________ techniques to answer different questions.
true
Generally, although sometimes called different things, the same statistics are used in most disciplines.
Tools and techniques
Statistics describes a set of __________ that is used for describing, organizing, and interpreting information.
Descriptive
statistics involve collecting, organizing, and summarizing data.
the average
What should be used to determine central tendency?
mean
What is the most common average computed?
arithmetic average
What is another term for the mean?
mean
What value is most often used to represent an entire group of scores?
skew
If a distribution is "significantly distorted" what is this called?
Sigma X/n
What is the formula for computing the mean?
X
Which of the following symbols represents the individual score?
4
If you know M = 5 and the sum of scores is 20, what is n?
1097.5
If n = 4 and ΣX / n, what is M?
variability
How much scores differ from one another or, put another way, the amount of spread or dispersion in a set of scores.
standard deviation
The average amount of variability in a set of scores or the scores' average deviation from the mean.
mean deviation
The average deviation for all scores from the mean of a distribution, calculated as the sum of the absolute value of the scores' deviations from the mean divided by the number of scores.
unbiased estimate
A conservative estimate of a population parameter.
variance
The square of the standard deviation and another measure of a distribution's spread or dispersion.
variability
Which of the following measures how scores differ from each other?
range
Which measure of variability is easiest to calculate?
33
What is the range for the following set of scores: 29, 48, 22, 37, 55?
variability
When reporting descriptive data such as the Mean, what additional information should also be reported that expresses how different the scores are in the distribution?
the exclusive range
The highest score minus the lowest score is equal to:
s
Which of the following is one way to represent the standard deviation?
11.29
What is the variance for the following set of scores: 10, 15, 12, 18, 19, 16, 12?
standard deviation
What is the square root of the variance?
2.90
Σ(X - M)2 = 235, and n = 29, what is "s"
25
If you have a standard deviation of 5, your variance will be:
frequency distribution
A method for illustrating how often scores occur in groups called class intervals.
class interval
A fixed range of values, used in the creation of a frequency distribution.
histogram
A graphical representation of a frequency distribution that uses bars of different heights to show the number of values that fall within each class interval
midpoint
The central point in a class interval
frequency polygon
A graphical representation of a frequency distribution that uses a continuous line to show the number of values that fall within a class interval.
cumulative frequency distribution
A frequency distribution that shows frequencies for class intervals along with the cumulative frequency at each
ogive
A visual representation of a cumulative frequency distribution.
skewness
The quality of a distribution that defines the disproportionate frequency of certain scores. A longer right tail than left corresponds to a smaller number of occurrences at the high end of the distribution; this is a positively skewed distribution. A shorter right tail than left corresponds to a larger number of occurrences at the high end of the distribution; this is a negatively skewed distribution
kurtosis
The quality of a distribution that defines how flat or peaked it is.
platykurtic
The quality of a normal curve that is relatively flat compared to a normal distribution
leptokurtic
The quality of a normal curve that is relatively peaked compared to a normal distribution.
maintain the scale in the graph
Which of the following are among the things to remember when creating figures?
Make sure your graph communicates only one idea
A good rule of thumb when creating an illustration is:
negatively skewed
A distribution of scores in which almost the entire class scored very high, but a few students scored fairly low, would be:
5
If you have a distribution of 100 scores and you want 20 intervals, what should be the size of your class interval?
10 to 20
Optimally, when choosing a class interval, you should have approximately this many intervals covering the entire range of data:
Histogram
What type of chart or graph displays class intervals along an x-axis?
cumulative frequency distribution
What is the frequency distribution that shows frequencies for class intervals along with the cumulative frequency for each?
Kurtosis
What is the term associated with how flat or peaked a distribution appears?
y-axis
What is the vertical axis on a graph called?
mean/ median
If a distribution is positively skewed, the ________ is greater than the __________.
correlation coefficient
A numerical index that reflects the relationship between two variables, specifically how the value of one variable changes when the value of the other variable changes
direct correlation
A positive correlation where the values of both variables change in the same direction.
indirect correlation
A negative correlation where the values of variables move in opposite directions.
scatterplot
A plot of paired data points on an x- and a y-axis, used to visually represent a correlation.
scattergram
A plot of paired data points on an x- and a y-axis, used to visually represent a correlation.
linear correlation
A correlation that is best expressed visually as a straight line.
correlation matrix
A table showing correlation coefficients among more than two variables.
coefficient of alienation
The amount of variance in one variable that is not accounted for by the variance in another variable.
Karl Pearson
Who is responsible for the invention of the Pearson product-moment correlation coefficient?
Phi coefficient
Which of the following is an example of a correlation?
a group
Correlation coefficients are used to describe:
Bivariate
Which of the following refers to a correlation between two variables?
-1.0 to 1.0
Which of the following illustrates the range of possible values of Pearson's product-moment correlation coefficient?
negative correlation
If variables change in the opposite direction, what type of correlation is this called?
rxy
The correlation between variable X and variable Y is represented by which of the following?
scatterplot
What would you use to visually represent a correlation?
49%
If the correlation between variables is .70, what percent of the variance is shared variance?
.45
Which of the following correlations would be interpreted a moderate relationship?
dependent variable
The outcome variable or the predicted variable in a regression equation.
independent variable
The treatment variable that is manipulated or the predictor variable in a regression equation.
scales of measurement
Different ways of categorizing measurement outcomes: nominal, ordinal, interval, and ratio
nominal level of measurement
The most gross level of measurement by which a variable's value can be placed in one and only one category.
ordinal level of measurement
A level of measurement that places a variable's value into a category and assigns that category an order with respect to other categories.
interval level of measurement
A level of measurement that places a variable's values into categories that are order equidistantly from each other, as when points are evenly spaced along a scale.
ratio level of measurement
A level of measurement defined as having an absolute zero.
true score
The score that, if it could be observed, would reflect the actual ability or behavior being measured. See Observed score.
error score
The part of a test score that is random and contributes to the unreliability of a test.
parallel forms reliability
A type of reliability that examines consistency across different forms of the same test.
nternal consistency reliability
A type of reliability that examines whether items on a test measure only one dimension, construct, or area of interest.
construct validity
How well a test reflects an underlying idea, such as intelligence or aggression.
Descriptive statistics
Values that organize and describe the characteristics of a collection of data, sometimes called a data set.
Inferential statistics
Tools that are used to infer characteristics of a population based on data from a sample of that population.
frequency distribution
a method of tallying and representing how often certain scores occur
histogram
a visual representation of the frequency distribution where the frequencies are represented by bars
correlation coefficient
is a numerical index that reflects the relationship between two variables
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