Question

A research scientist wants to know how many times per hour a certain strand of bacteria reproduces. The mean is found to be 11.4 reproductions and the population standard deviation is known to be 22. If a sample of 375 was used for the study, construct the 90% confidence interval for the true mean number of reproductions per hour for the bacteria. Round your answers to one decimal place.

Lower Endpoint:

Upper Endpoint:

Answer 1

Given that,

Sample size = n = 375

Z/2 = 1.645

Margin of error = E = Z/2* ( /n)

= 1.645 * (22 / 375)

Margin of error = E = 1.9

At 90% confidence interval estimate of the population mean is,

- E < < + E

11.4 - 1.9 < < 11.4 + 1.9

9.5 < < 13.3 , (9.5 ,13.3)

Lower Endpoint = 9.5 ,Upper Endpoint = 13.3 .