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) Wilcoxon rank sum test B) Pooled-variance t test
C) McNemar test D) Paired t test
Q. 2To test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course. Suppose the before and after exam scores are both normally distributed. Which of the following tests will be the most appropriate?
A) Pooled-variance t test B) McNemar test
C) Wilcoxon rank sum test D) Paired t test
Q. 3The use of preservatives by food processors has become a controversial issue. Suppose 2 preservatives are extensively tested and determined safe for use in meats. A processor wants to compare the preservatives for their effects on retarding spoilage. They will choose to use the preservative that can keep the meat fresh for the longest amount of time. Suppose 15 cuts of fresh meat are treated with preservative I and 15 are treated with preservative II, and the number of hours until spoilage begins is recorded for each of the 30 cuts of meat. Suppose the variability of the number of hours until spoilage is the same for meat treated by both preservatives but the normal probability plots reveal that the number of hours until spoilage is right-skewed for the 15 cuts treated by preservative I and left-skewed for the 15 cuts treated with preservative II. Which of the following tests will be the most appropriate?
A) Levene's test B) Wilcoxon rank sum test
C) Pooled-variance t test D) Paired t test
Q. 4A researcher randomly sampled 30 graduates, 18 males and 12 females, of an MBA program and recorded data concerning their starting salaries. Of primary interest to the researcher was the effect of gender on starting salaries. Statistics of the mean salaries of the females and males in the sample were computed. The sample standard deviations suggest that the variability of starting salaries of the two groups is almost the same. Suppose the starting salaries from both groups can be considered as normally distributed. Which of the following tests will be the most appropriate?
A) Pooled-variance t test B) Wilcoxon rank sum test.
C) Separate-variance t test D) Paired t test
Q. 5Are Japanese managers more motivated than American managers? A randomly selected group of 100 managers from each group were administered the Sarnoff Survey of Attitudes Toward Life (SSATL), which measures motivation for upward mobility. The mean and standard deviation of the SSATL scores are computed. The standard deviations of the SSATL scores suggest that the standard deviation from the two groups is very different. Which of the following tests will be the most appropriate?
A) t test for the mean B) Z test for the proportion
C) Pooled-variance t test D) Separate-variance t test
Quick Reply
