Chapter 9: Correlational Research

Question 1

What are psychology’s two main dsciplines?

Answer 1

correlational and experimental psychology

Question 2

Describe the method of concomitant variation

Answer 2

changes in the value of one variable are accompanied by predictable changes in a second variable.
The strength of a correlation is indicated by the size of the coefficient of correlation, the most common one being Pearson’s r.

Question 3

What are the most common correlation coefficients and what kind of data is each one used for?

Answer 3

Pearson’s r is calculated for data measured on an interval or a ratio scale.
Spearman’s rho is calculated for ordinal data.
A chi-square test of independence works for nominal data.

Question 4

What is a drawback of Pearson’s r?

Answer 4

It fails to identify non-linear relationships

Question 5

Range restriction ____ the observed correlation

Answer 5

weakens

Question 6

What type of error would be observed if an outlier is included when calculating Pearson’s r?

Answer 6

Type I error

Question 7

What is the coefficient of determination (r2)?

Answer 7

the portion of variability in one of the variables in the correlation that can be accounted for by variability in the second variable

Question 8

What is regression analysis used for?

Answer 8

making predictions based on correlational research

Question 9

What do variables X and Y represent in a regression line?

Answer 9

X: predictor
Y: criterion

Question 10

What are two problems a researcher is faced with when interpreting correlations?

Answer 10

the directionality problem and third variable problem

Question 11

explain the directionality problem

Answer 11

if there’s a correlation between variables A and B, it is equally possible that A is causing B (A → B) or that B is causing A (B → A)

Question 12

explain the third variable problem

Answer 12

rather than A causing B or B causing A, an unknown third variable C might be causing both A and B

variable C is also called a confounder

Question 13

How do you counter the directionality problem?

Answer 13

by using a cross-lagged panel correlation

Question 14

what is a cross-lagged panel correlation?

Answer 14

a longitudinal procedure which investigates correlations between variables at several points in time

Question 15

How do you counter the third variable problem?

Answer 15

By using partial correlation

Question 16

What is partial correlation?

Answer 16

A procedure that statistically controls for third variables if you suspect a specific measurable third variable

Question 17

name some fields where correlational research is used

Answer 17

• assessing validity and reliability of psychological tests
• personality psychology
• abnormal psychology
• twin studies

Question 18

What is the difference between a bivariate and multivariate analysis?

Answer 18

A bivariate approach investigates the relationships between any two variables.
A multivariate approach examines the relationships among more than two variables.

Question 19

What is shown in the following image?

Answer 19

y = dependent variable
x = independent variable
b = regression weight

R → correlation between the combined predictors and the criterion
R2 → variation in criterion variable that can be accounted for by the combined predictors

Question 20

What is a factor analysis?

Answer 20

Multiple variables are measured and correlated with each other. It is then determined whether groups of these variables cluster together to form factors. Pearson’s r can be calculated for all possible pairs of tests, yielding a correlation matrix. The analysis also determines factor loadings - correlations between each of the measures and factors.

Question 21

what is the advantage of multiple regression analysis

Answer 21

predictive validity improves when the influences of several predictor variables are combined, compared to single regression analysis