Question

12 randomly selected adult subject sleep times were obtained with sample mean equal to 6.833 hours and sample standard deviation equal to 1.992 hours. Use the p-value method and a .05 significance level to test the claim that the mean amount of sleep for adults is less than 7 hours. Assume normality.

Answer 1

This is the left tailed test .

The null and alternative hypothesis is

H₀ : = 7

H_a : < 7

Test statistic = t

= ( - ) / s / n

= (6.833 - 7) / 1.992 / 12

Test statistic = -0.2904

df = 11

P-value = 0.3885

= 0.05

P-value >

Fail to reject the null hypothesis .