Question

The average US woman wears 515 chemicals on an average day from her makeup and toiletries. A random sample from California found that on average the California woman wears 325 chemicals per day with a standard deviation of 90.5.Which hypothesis test should be used to determine whether the sample contains less than the US average of wearing 515 chemicals per day?a. t-test for the population meanb. z-test for the population meanc. z-test for the population proportiond. t-test for the population proportion

Answer 1

a. t-test for the population mean

Explanation:

given that the average US woman wears 515 chemicals on an average day from her makeup and toiletries

A random sample from California found that on average the California woman wears 325 chemicals per day with a standard deviation of 90.5.

Note that here we have only sample std deviation and not population.

So better to use t test here.

Sample size is not given so whatever be the sample size here t test would be more appropriate.

Here we are testing for mean. So the correct answer is

a. t-test for the population mean