PSYC 2317

Mark W. Tengler, M.S.

Assignment #4

Correlation

4.1What information is provided by the sign (+ or -) of the Pearsoncorrelation?

4.2What information is provided by the numerical value of the Pearson correlation?

4.3For the following set of data:

XY

12

34

46

55

76

a.Sketch a graph showing the location of the five X,Y points.

b.Just looking at your graph, estimate the value of the Pearson correlation.

c.Compute the Pearson correlation for this data set using the formula sheet handed out in

class.

4.4It is well known that similarity in attitudes, beliefs, and interests plays an important

role in interpersonal attraction (see Byrne, 1971, for example). Thus, correlations for attitudes

between married couples should be strong. Suppose a researcher developed a questionnaire that

measures how liberal or conservative one'sattitudesare.Low scores indicate that the person

has liberal attitudes, whereas high scores indicate conservatism. The following hypothetical data

are scores for married couples.

CoupleWifeHusband

A17

B42

C23

D16

E32

F06

G23

H25

PSYC 2317

Mark W. Tengler, M.S.

Compute the Pearson correlation for these data (previous page), and determine:

a.whether or not there is a relationship between attitudes for husbands and wives (yes or

no). Explain your answer.

b.what type of relationship there is, if any (positive or negative). Explain your answer.

c.how strong or weak the relationship is, if any. How do you know?