TABLE 10-8
a Buyer for a Manufacturing Plant Suspects That

question 26

Short Answer

TABLE 10-8
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.
$\begin{array}{crrr}&\text { Primary}&\text { Secondary }\\\underline{\text {Material }}&\underline{\text {Supplier}}&\underline{\text { Supplier }}&\underline{\text {Difference }}\\1 & \$ 55 & \$ 45 & \$ 10 \\2 & \$ 48 & \$ 47 & \$ 1 \\3 & \$ 31 & \$ 32 & -\$ 1 \\4 & \$ 83 & \$ 77 & \$ 6 \\5 & \$ 37 & \$ 37 & \$ 0 \\6 & \$ 55 & \$ 54 & \$ 1 \\\hline \text { Sum: } & \$ 309 & \$ 292 & \$ 17\\\text { Sum of Squares: } &\$ 17,573& \$ 15,472 &\$ 139\end{array}$






-Referring to Table 10-8, what is the 90% confidence interval estimate for the mean difference in prices?

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Definitions:

L-Lysine

An essential amino acid in humans, important for protein synthesis and other metabolic functions, characterized by its aliphatic side chain.

Biological pH

Refers to the pH level within living organisms or biological systems that is maintained at a constant range essential for life processes.

Predominant Form

The most stable or frequently occurring form of a molecule under given conditions.

Lysine

An essential amino acid required for growth and tissue repair, not synthesized by the body and must be obtained from the diet.