Research Design

Question 1

Predictive value

Answer 1

the degree to which an independent variable can predict a dependent variable

Question 2

Cohort effects

Answer 2

the effects that might result when a group is born and raised in a particular time period.

Question 3

Demand characteristic

Answer 3

when subjects act in ways they think the experimenter wants or expects

Question 4

Experimenter bias (another name)

Answer 4

Rosenthal effect

Question 5

Hawthorne effect

Answer 5

when subjects alter their behavior because they’re being observed

Question 6

Selective attrition

Answer 6

when the subjects that drop out of an experiment are different from those that remain. Remaining sample is no longer random

Question 7

Social desirability

Answer 7

subjects do and say what they think puts them in a positive light.

Question 8

Frequency distributions

Answer 8

explain how the data in a study looked. Might show how often different variables appeared.

Question 9

Nominal variables

Answer 9

male/female; Republican/democrat

Question 10

Ordinal variables

Answer 10

implies order; not necessarily equally spaced (marathon finishers)

Question 11

Interval variables

Answer 11

show order and space because equal spaces lie between the variables, but do not include a real zero (temperature)

Question 12

Ratio variables

Answer 12

order, equal intervals, and a real zero (age)

Question 13

Frequency polygon

Answer 13

plotted points connected by lines; used to plot continuous variables (categories without clear boundaries)

Question 14

Histogram

Answer 14

vertical bars; sides touch; discrete variables with clear boundaries and interval variables with some order

Question 15

Standard deviation

Answer 15

(1) subtract mean from each; (2) square each; (3) add; (4) divide by original number of scores; (5) take square root

If standard deviation is large – scores highly dispersed
If small, scores very close together

Question 16

Unimodal

Answer 16

only one hump

Question 17

Z-score

Answer 17

how many standard deviations a score is from the mean; -3 to +3 for normal distributions

Question 18

T-score

Answer 18

transformation of a z-score in which the mean is 50 and the standard deviation is 10; T = 10(z) + 50

Question 19

Standard normal distribution

Answer 19

same as normal distribution but standardized so that the mean for every distribution is zero and the standard deviation is one

Question 20

platykuric distributions

Answer 20

flat top/same sides

Question 21

Pearson r correlational coefficient

Answer 21

• 1 to +1

Question 22

Spearman r correlational coefficient

Answer 22

used only when data is in the form of ranks – used to determine the line that describes a linear relationship

Question 23

Statistical regression

Answer 23

allows you to not only identify a relationship between two variables but also make predictions about one variable based on another variable

Question 24

Parameters

Answer 24

refer to numbers that describe populations

Question 25

statistically significant

Answer 25

describes a real pattern

Question 26

Alpha level

Answer 26

significance level; < .05 or < .01 (5/100 or 1/100)

Question 27

Type 1 error

Answer 27

incorrectly reject the null hypothesis (thought findings were significant but they weren’t)

Question 28

Type 2 error

Answer 28

wrongly accept the null hypothesis (say no relationship, but there is)

Question 29

T-test

Answer 29

compare the means of two different groups to see if the two groups are truly different; used to analyze means on continuous data; particularly useful when samples are small; cannot test for differences between two groups

Question 30

Chi-square tests

Answer 30

used when n-cases in a sample are classified into categories (cells); tells us whether the groups are statistically significant in size; analyze categorical or discrete data; can be used on small samples; can assess goodness of fit of distribution or whether the pattern is what would be expected

Question 31

ANOVA (Analysis of variance):

Answer 31

analyzes differences among means of continuous variables; can analyze difference among more than two groups

Question 32

One-way ANOVA

Answer 32

tests whether the means on one outcome or dependent variable are significantly different across groups

Question 33

Two-way ANOVA

Answer 33

tests effects of 2 independent variables or treatment conditions at once

Question 34

Factorial analysis of your variance

Answer 34

Used when an experiment involves more than one independent variable; can isolate main effect; can identify interaction effects

Question 35

Analysis of Covariance (ANCOVA)

Answer 35

• Tests whether two groups co-vary; can adjust for preexisting differences between groups

Question 36

Linear regression

Answer 36

Use correlational coefficients as a predictive measure; based on a line fit with the least-squares method

Question 37

standardized

Answer 37

tried out on huge groups of people to create norms

Question 38

Criterion-referenced tests

Answer 38

measure mastery in one particular area (final exam)

Question 39

Domain-referenced tests

Answer 39

attempt to measure less defined properties (like intelligence); need to be checked for reliability and validity

Question 40

Reliability

Answer 40

how stable the measure is

Question 41

Split-half reliability

Answer 41

comparing an individual’s performance on two-halves of the same measure (odd vs. even); reveals internal consistency

Question 42

Item-analysis

Answer 42

how a large group responded to each item on a measure

Question 43

Concurrent validity

Answer 43

whether scores on a new measure positively correlate with other measures known to test the same construct • Cross-validation

Question 44

Construct validity

Answer 44

whether the test really taps the abstract concept being measured

Question 45

Content validity

Answer 45

whether the content of the test covers a good sample of the construct (not just a part of it)

Question 46

Face validity

Answer 46

test whether the items simply look like they measure the construct

Question 47

Donald Campbell and Donald Fiske

Answer 47

multi-trait-multi-method technique to determine the validity of tests