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? a. z - test for the population mean b. t - test for the population mean c. z - test for the population proportion d. t - test for the population proportion

Explanation:

We are testing a claim about the population mean (average number of adenoviruses per liter). The population standard - deviation is unknown, and we have a sample standard deviation. For a sample size \(n = 45\) (where \(n>30\) but the population standard - deviation \(\sigma\) is unknown), we use the t - test for the population mean.

Answer:

B. t - test for the population mean