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47 terms

AP_Stats_2010-11

Ap Stats Vocab - specifically For Experimental design
STUDY
PLAY
Bias
a college has 80% full time students and 20% part time. I do a survey of 500 students and on purpose survey 50% full time students and 50% part time. , influence in an unfair way
Blind Experiment
an experiment in which the subjects do not know whether they are members of the experimental group or the control group.
Blocking
using extraneous factors to create experimental groups that are similar with respect to those factors, thereby filtering out their effect
Confounding
a variable that can be affecting your experiment.
Control
A sample that is treated like other experimental groups except that the independent variable is not applied to it
Double Blind
a test procedure in which the identity of those receiving the intervention is concealed from both the administrators and the subjects until after the test is completed
Experiment
the act of conducting a controlled test or investigation
Experimental Design
A design in which researchers manipulate an independent variable and measure a dependent variable to determine a cause-and-effect relationship
Factor
A commercial asks you to buy something frequently mention a toll-free number. "toll free number" and "price" are examples of this term.
Hidden Bias
The question may be worded in such a way as to elicit specific response. The ordered of questions might lead to biased responses. Also, the number or response on a Likert scale may force responses that do not reflected the respondent's feelings or experience.
Level
In one of the previous examples about commercials, commercials were shown where the toll free number was mentioned 1,3, or 4 times, and the price mentioned 2 and 3 times. There numbers each form a different ____.
Matched Pairs
an observational technique that involves matching each participant in the experimental group with a specific participant in the control group in order to eliminate the possibility that a third variable (and not the independent variable) caused changes in the dependent variable
Multistaged Sample
A sample that involved multiple stages to carry out.
nonresponse
occurs when an individual chosen for the sample can't be contacted or does not cooperate
observational study
a study in which the researcher carefully and systematically observes and records behavior without interfering with the behavior; it may involve either naturalistic or laboratory observation
poorly worded question
A question that prompts a certain response.
population
(statistics) the entire aggregation of items from which samples can be drawn
probability sampling design
sampling design most commonly used in qualitative research
randomization
random assignment of experimental units to treatments or of treatments to trials, the best defense against bias.
replication
the repetition of an experiment in order to test the validity of its conclusion
sample
items selected at random from a population and used to test hypotheses about the population
sampling frame
the individuals or clusters of individuals who might actually be selected for inclusion in the sample
simple random sample
this of sample size n is one in which each set of n elements in the population has an equal chance of selection
statistical inference
Making inferences about the characteristics of the population from the information that is provided by the sample.
statistically significant
a term used to describe research results when the outcome of a statistical test indicates that the probability of those results occurring by chance is small
stratified random sample
a sample in which the population is first divided into similar, nonoverlapping groups. A simple random sample is then selected from each of the groups
table of random digits
A long string of digits 0-9, each with these properties, each entry is equally likely to be any of the 10 digits. Entries are independent
treatment
I give a set of students a pre-test on their knowledge on the civil war. Then i give them a chapter to read on the subject. Then I give them a post test. The chapter they read would be an example of ____.
undercoverage
a sampling scheme that biases the sample in a way that gives a part of the population less representation than it has in the population
voluntary response sample
A sample that consists of people who choose themselves by responding. They often over represent people with strong opinions.
Cluster sample
a sampling design in which entire groups, aka Clusters, are chosen at random. usually selected at a matter of convenience, practicality or cost. each cluster should be diverse in character and representitive of the population, so all the clusters should be similar to each other
response bias
preconceived notions of a person answering [a survey] which may alter the experiments purpose, anything in the survey design that influences the responses from the sample.
convenience sample
when researchers draw participants from the populations that are readily available to them
voluntary response sample
A sample that consists of people who choose themselves by responding. They often over represent people with strong opinions.
representative sample
the population is divided into strata and a random sample is taken from each stratum, sample carefully chosen so that the characteristics of the participants correspond closely to the characteristics of the larger population
population of interest
all of the individuals from which subjects for an experiment may be drawn
placebo
something presented as a drug (or whatever you are trying to test in your experiment), but having no actual effect on the person.
linearity
the notion that one event is a cause and the other is its effect; in behavior, the idea that one behavior is a stimulus and the other a response. Linear thinking is opposite of circular thinking, in which events are thought to be related in a series of interacting loops
clusters
set of similar things grouped together; bunches
outliers
Numbers that are much greater or much less than the other numbers in the set
least squares regression line
The least-squares regression line of y on x is the line that makes the sum of the squares of the vertical distances of the data points from the line as small as possible.
correlation coefficient
a statistic representing how closely two variables co-vary. -1 to 1
explanatory variable
the independent variable that attempts to explain the relationship with the other variable. It becomes the x variable on the graph
response variable
values of this variable record the results of each trial with respect to what we were interested in
scatterplot
a graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation). (Also called a scattergram or scatter diagram.) (Myers Psychology 8e p. 031)
residual
the difference between a Y value estimated from the regression equation and the actual Y value for each unit - the lower the values of r, the larger the residuals will be
coefficient of variation
A measure of relative variability that indicates risk per unit of return. In general, it is equal to the standard deviation divided by the mean value.