Question

Water safety standards in southern California suggest that if a concentration of adenoviruses in the water is more than 1,000 per liter, further testing would have to be done to determine if the water was hazardous. A random sample of 45 water sources around San Diego showed an average of 1,023 adenoviruses per liter, with a standard deviation of 138.9. Which hypothesis test should be used to determine if the water samples contain more than the allowed 1,000 adenoviruses per liter

Answer 1

I should use a t-distribution test.

Explanation:

A t-distribution test is used in lieu of a standard normal distribution test if the population standard deviation is unknown.

In this case, the population standard deviation is unknown but the sample standard deviation is known, therefore, a t-distribution hypothesis test is appropriate to use.