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Suppose the KittyCat brand of litter products manufactures 15 lb bags of litter. Lisa, a cat owner, believes that these bags contain less than 15 lb of litter. She collects data on a randomly selected sample of 70 KittyCat 15 lb litter bags and decides to use a hypothesis test to determine whether the mean weight is less than 15 lb. Lisa believes that the weight of all such bags of litter is normally distributed, but she does not know the population standard deviation. Which of the following hypothesis tests should Lisa use regarding her claim?
a. one-sample, right-tailed z-test for a mean
b. one-sample, right-tailed 1-test for a mean
c. one-sample, left-tailed t-test for a mean
d. one-sample, left-tailed z-test for a mean
e. one-sample, two-tailed t-tes for a mean

Respuesta :

Considering that she does not know the population standard deviation, the hypothesis test that she should use is given by:

c. one-sample, left-tailed t-test for a mean.

What hypothesis test should she use?

First, we consider that she does not know the population standard deviation, hence a t-test should be used instead of a z-test.

Then, we consider that she suspects that the mean weight is less than 15 lb, and less is associated with a left-tailed test, instead of a right-tailed(associated with more) or a two-tailed(associated with different).

Hence option c is correct.

More can be learned about an hypothesis test at https://brainly.com/question/26454209