Question

Identifying individuals with a high risk of Alzheimer’s disease usually involves a long series of cognitive...

Identifying individuals with a high risk of Alzheimer’s disease usually involves a long series of cognitive tests. However, researchers have developed a 7-Minute Screen, which is a quick and easy way to accomplish the same goal. The question is whether the 7-Minute Screen is as effective as the complete series of tests. To address this question, Ijuin et al. (2008) administered both tests to a group of patients and compared the results. The following data represent results similar to those obtained in the study.

Patient

7-Minute Screen

Cognitive Series

A

3

11

B

8

19

C

10

22

D

8

20

E

4

14

F

7

13

G

4

9

H

5

20

I

14

25

A) Compute the Pearson Correlation Coefficient for these data.

r =

Note: For all the calculations, if it is a decimal number with two or more than two places, leave only two decimal places after the decimal point and do not round.

If it is a negative correlation, please do not forget to include the negative sign.

B) The correlation is

Medium and negative

Large and negative

Large and positive

Medium and positive

C) The null hypothesis for a two-tailed test is

The correlation between the scores on the 7-minute screen test and the scores on the cognitive series is significant

The correlation between the scores on the 7-minute screen test and the scores on the cognitive series is not significant

The correlation between the scores on the 7-minute screen test and the scores on the cognitive series is less than zero

The correlation between the scores on the 7-minute screen test and the scores on the cognitive series is different from zero

D) The alternative hypothesis in symbols for a two-tailed test is

H1: ρ = 0

H1: ρ ≠ 0

H1: r = 0

H1: r ≠ 0

E) If we use a two-tailed test with α = .01, the critical r values are:

±0.666

±0.582

±0.798

±0.750

F) Your decision is:

Reject the null hypothesis and conclude that there is a significant correlation between the scores on the 7-minute screen test and the scores on the cognitive series

Fail to reject the null hypothesis and conclude that there is a significant correlation between the scores on the 7-minute screen test and the scores on the cognitive series

Reject the null hypothesis and conclude that there is no significant correlation between the scores on the 7-minute screen test and the scores on the cognitive series

Fail to reject the null hypothesis and conclude that there is no significant correlation between the scores on the 7-minute screen test and the scores on the cognitive series

G) Report the results in APA

Math   Statistics-And-Probability   
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