TABLE 10-7
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. The data collected is presented in the table below, with some summary statistics presented (all of these might not be necessary to answer the questions which follow). The buyer believes that the differences are normally distributed and will use this sample to perform an appropriate test at a level of significance of 0.01.
-Referring to Table 10-7, the test to perform is a
A) pooled-variance t test for differences between two means.
B) one-way ANOVA F test for differences among more than two means.
C) Z test for the difference between two proportions.
D) paired t test for the mean difference.

Question

TABLE 10-7
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. The data collected is presented in the table below, with some summary statistics presented (all of these might not be necessary to answer the questions which follow). The buyer believes that the differences are normally distributed and will use this sample to perform an appropriate test at a level of significance of 0.01. 
-Referring to Table 10-7, the test to perform is a
A) pooled-variance t test for differences between two means. 
B) one-way ANOVA F test for differences among more than two means. 
C) Z test for the difference between two proportions. 
D) paired t test for the mean difference.

Quizplus · Accepted Answer

The table presents data on two groups of prices (primary and secondary suppliers) that are being compared. Additionally, it is stated that the buyer wants to compare these prices, suggesting a paired comparison between the prices of each supplier for the identical materials. Therefore, the appropriate test to perform is a paired t test for the mean difference.

TABLE 10-7 A Buyer for a Manufacturing Plant Suspects That His Primary