Question

Based on interviews with

8686

SARS​ patients, researchers found that the mean incubation period was

4.44.4

​days, with a standard deviation of

15.315.3

days. Based on this​ information, construct a​ 95% confidence interval for the mean incubation period of the SARS virus. Interpret the interval.

The lower bound is

nothing

days.​ (Round to two decimal places as​ needed.)

Answer 1

Solution :

Given that n = 86 , mean x-bar = 4.4 , standard deviation s = 15.3

=> df = n - 1 = 85

=> For 95% confidence interval, t = 2.228

=> A 95% confidence interval of the mean incubation period of the SARS virus is

=> x-bar +/- t*s/sqrt(n)

=> 4.4 +/- 2.228*15.3/sqrt(86)

=> (0.7242 , 8.0758)

=> (0.72 , 8.08) (rounded)

=> There is a 95% confidence that the mean incubation period lies between the lower and the upper bounds of the interval