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A study of the effects of exercise used rats bred to have high or low capacity f

ID: 3156745 • Letter: A

Question

A study of the effects of exercise used rats bred to have high or low capacity for exercise. The 8 high-capacity rats had mean blood pressure 89 and standard deviation 9; the 8 low-capacity rats had mean blood pressure 105 with standard deviation 13. (Blood pressure is measured in millimeters of mercury, mm Hg.)

1. To compare the mean blood pressure of the two types of rats with a t procedure, the correct degrees of freedom is____?

2. The two-sample t statistics for comparing the two population means has value ____?

3.The p-value for testing the hypotheses from the previous exercise satisfies

(a) 0.005<P<0.01

(b) 0.01 <P<0.02

(c) 0.02<P<0.05

4.The margin of error of a 95% confidence interval for mean of High Capacity vs mean of low capacity is approximately

Explanation / Answer

1) df = 8+8-2 = 14

2)

t = ( 89 - 105) / srqt ( 9^2+13^2 / 8 )

t = -2.862

p value is between 0.005 and 0.01

4)

margin of error 95% alpha / 2 = 0.025

t= 2.145

margin of error : 2.145*srqt ( 9^2+13^2 / 8 )

argin of error : 11.99