Question 750481
a. 95% Confidence Interval for the standard deviation:
(3.694, 7.738)

95% Confidence Interval for the variance:
(13.642, 59.884)

b.
Null Hypothesis: σ = 10
Alternative Hypothesis: &#963; < 10

&#945; = 0.05

Test Statistic, Chi Square =  3.75
Critical Value = 7.2610


Reject the Null Hypothesis because the test value is less than the critical value. Sample provides evidence to support the claim that the population standard deviation of hours spent studying is less than 10 hours.