A buyer for a manufacturing plant suspects that his primary supplier of raw materials is overcharging. In order to determine if his suspicion is correct, he contacts a second supplier and asks for the prices on various identical materials. He wants to compare these prices with those of his primary supplier. He collected data on 6 different materials from both suppliers. He believes that the differences are normally distributed. Which of the following tests will be the most appropriate?
A) pooled-variance t test
B) paired t test
C) Wilcoxon rank sum test
D) McNemar test

Question

Quizplus · Accepted Answer

The paired t test is the most appropriate as the buyer is comparing prices on identical materials from two different suppliers. The paired t test is used to compare two means from two dependent samples, which is the case here as the materials being compared are identical. The other options are not appropriate as they are either for non-normal distributions (Wilcoxon rank sum) or for categorical data (McNemar). The pooled-variance t test may be used if the variances of the two samples are equal, but it is not necessary in this case.

A Buyer for a Manufacturing Plant Suspects That His Primary