   Chapter 11, Problem 14P Essentials of Statistics for the B...

8th Edition
Frederick J Gravetter + 1 other
ISBN: 9781133956570

Solutions

Chapter
Section Essentials of Statistics for the B...

8th Edition
Frederick J Gravetter + 1 other
ISBN: 9781133956570
Textbook Problem

Researchers have noted a decline in cognitive functioning as people age (Bartus, 1990). However, she results front other research suggest that the antioxidants in foods such as blueberries may reduce and even reverse these age related declines (Joseph et al., 1999). To examine this phenomenon, suppose that a researcher obtains a sample of n = 16 adults who are between the ages of 65 and 75. The researcher uses a standardized test to measure cognitive performance for each individual. The participants then begin a 2-month program in which they receive daily doses of a blueberry supplement. At the end of the 2-month period the researcher again measures cognitive performance for each participant. The results show an average increase in performance of MD= 7.4 with SS = 1215.a. Does this result support the conclusion that the antioxidant supplement has a significant effect on cognitive performance? Use a two-tailed test with α = .05.b. Construct a 95% confidence interval to estimate the average cognitive performance improvement for the population of older adults.

a.

To determine
The significance effect of antioxidant supplement on cognitive performance using two tail test.

Explanation

Given info:

The average of student MD is 7.4, variance SS is 1215 and n is 16.

Calculation:

Given that MD is 7.4 and variance SS is 1215.

The null hypothesis:

H0:μD=0 (There is no difference between the two tests)

The alternative hypothesis:

H1:μD0  (There is difference between the two tests)

The sample variance:

s2=SSn1

s2=1215161=121515=81

Thus, the sample variance is 81

b.

To determine
The confidence interval to estimate the average cognitive at 95%.

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