Suppose we were interested in determining if there were differences in the average prices among two local supermarkets. We randomly take the average of 40 items with each store to compare both supermarkets, and we want to know if there is a difference in the average price of grocery items.

We computed a hypothetical mean price of items and standard deviation for each supermarket. Which statistical procedure would be best to use for this study?

1. Dependent or pairs t-test

2.Chi-squared test for independence

3.Z-test for independent groups

4.Independent t-test

5.Independent z-test