Quiz7

1. The closer the points on a scatter diagram fall to the regression line, the high the correlation between the scores.

a.higher the correlation

b.lower the correlation

c.correlation doesn't change

d.need more information

2. The weakest degree of correlation shown below is 0.15.

a.0.75

b.-0.33

c.-0.25

d.0.15

3. If the correlation between two variables is -1.00 and the score of a given individual is 2.20 standard deviations above the mean on one of the variables, we would predict a score on the second variable of more than 2.20 standard deviations below the mean

a.2.20 standard deviations below the mean

b.2.20 standard deviations above the mean

c.more than 2.20 standard deviations above the mean

d.more than 2.20 standard deviations below the mean

4 Rho is used when one or both variables are only of ordinal scaling.

a.when both variables are dichotomous

b.when both variables are of interval or ratio scaling

c.when one or both variables are only of ordinal scaling

d.when the data is nonlinear

5. A traffic safety officer conducted an experiment to determine whether there is a correlation between people's ages and driving speeds. Six individuals were randomly sampled and the following data were collected.

Age

20

25

45

46

60

65

Speed (mph)

60

47

55

38

45

35

S X = 280S Y =261S XY = 11,573

S X2 = 13,528S Y2 =12,991

Steps to Calculate Pearson r through SPSS

Go to analyze

Then Go to Bi-variate

Then select Correlation

Input the Variables and then click Ok

Formula of Pearson r = ?XY - (?X)(?Y)

v (?X2-(?X)2 (?Y2- (?Y)2

nn

6. Refer to Case Study 6-1. The value of Pearson r equals -0.6.

a.-0.82

b.-0.70

c.-0.63

d.+0.70

7. Refer to Case Study 6-1. The proportion of variability of Y accounted for by X is 0.4.

a.0.49

b.0.67

c.0.40

d.-0.49

8. A researcher wanted to know if the order in which runners finish a race is correlated with their weight. She conducts an experiment and the data are given below.

Finishing order 123456

Weight (lbs)110114112108116113

9. Refer to Case Study 6-2. What is the appropriate correlation coefficient for this data? Rho

a.r

b.rho

c.phi

d.biserial

10. The regression equation most often used in psychology minimizes (Y - Y') 2 .

a. (Y - Y')

b. (Y - Y') 2

c. (Y - X) 2

e.none of the above

11. If two variables are ratio scaled and the relationship is linear, what type of correlation coefficient is most appropriate? Pearson

a.Pearson

b.Spearman

c.eta

d.Phi

12. A researcher collects data on the relationship between the amount of daily exercise an individual gets and the percent body fat of the individual. The following scores are recorded.

Individual

1

2

3

4

5

Exercise (min) x

18

26

33

44

10

% Fat(y)

30

25

18

17

14

S X = 131S Y =104S XY = 2395

S X2 = 4125S Y2 =2334

Steps to Calculate Slope of regression line (

Go to analyze

Then Go ...