Question

Question Hannah wanted to investigate whether there was a difference in the time spent in the checkout line between two grocery stores in a large city. She went to Grocery Store J on a Monday morning and recorded the time, in minutes, it took 30 customers to go through a checkout line. Then she went to Grocery Store K on Monday afternoon and recorded the time it took 30 customers to go through a checkout line. Hannah calculated the mean number of minutes for the customers in each line. She intends to conduct a two-sample t-test for a difference in means between the two stores. Have all conditions for inference been met?

Answer 1

Yes. All the conditions for inference have been met.

Explanation:

The conditions for inference are:

a) The sample must be random. The selections of the 30 customers in each Grocery Store were not biased in any way.

b) The sampling distribution must be approximately normal.

c) The observations of the samples were independent.

d) Adequate of sample size. 30 customers represent an adequate sample

e) The variances are not known as they were disclosed in this case.