Experimental Psychology

Front 1

dependent variable

Back 1

variable considered to be an effect

Front 2

independent variable

Back 2

variable considered to be a cause, such as what group a person is in for a t test or analysis of variance

Front 3

sample

Back 3

scores of a particular group of people studied; usually considered to be representative of the scores in some larger population

Front 4

population

Back 4

entire group of people to which a researcher intends the results of a study to apply; the larger group to which inferences are made on the basis of the particular set of people (sample) studied.

Front 5

Null hypothesis H0

Back 5

statement about a relation between populations that is the opposite of the research hypothesis; a statement that in the population there is no difference between populations

Front 6

alternative hypothesis HA

Back 6

statement in hypothesis testing about the predicted relation between populations

Front 7

Critical value (cutoff sample score)

Back 7

the point on the comparison distribution at which, if reached or exceeded by the sample score, you reject the null hypothesis

Front 8

directional hypothesis

Back 8

research hypothesis predicting a particular direction of difference between populations - for example, a prediction that the population like the sample studied has a higher mean than the population in general

Front 9

one-tailed test

Back 9

hypothesis-testing procedure for a directional hypothesis; situation in which the region of the comparison distribution in which the null hypothesis would be rejected is all on one side of the distribution

Front 10

nondirectional hypothesis

Back 10

research hypothesis that does not predict a particular direction of difference between the population like the sample studied and the population in general

Front 11

two-tailed test

Back 11

hypothesis testing procedure for a nondirectional hypothesis; the situation in which the region of the comparison distribution in which the null hypothesis would be rejected is divided between the two sides of the distribution

Front 12

experimental design

Back 12

the general plan for selecting participants, assigning participants to experimental conditions, controlling extraneous variables, and gathering data

Front 13

influences on power

Back 13

Effect size - large (increases power), small (decreases power)

predicted difference btwn pop means - large differences (increases power), small differences (decreases power)

pop std dev - small pop SD (increases), large pop SD (decreases)

Sample size (N) - large (increases), small (decreases)

sign level - lenient (increases), stringent (decreases)

one tailed (increases), two tailed (decreases)