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15 Cards in this Set
- Front
- Back
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The t test for the difference between the means of 2 independent populations assumes that the respective
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populations are approximately normal.
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In testing for differences between the means of two independent populations, the null hypothesis is
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H0: u1 - u2 = 0.
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The sample size in each independent sample must be the same if we are to test for differences between the means of two independent populations.
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False
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A statistics professor wanted to test whether the grades on a statistics test were the same for upper and lower classmen. The professor took a random sample of size 10 from each, conducted a test and found out that the variances were equal. For this situation, the professor should use a t test with related samples.
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False
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Are Japanese managers more motivated than American managers? A randomly selected group of each were administered the Sarnoff Survey of Attitudes Toward Life (SSATL), which measures motivation for upward mobility. The SSATL scores are summarized below.
REF QUIZ 10 #5 Table 10-1 Referring to Table 10-1, judging from the way the data were collected, which test would likely be most appropriate to employ? |
Pooled-variance t test for the difference between two means
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TABLE 10-1
Are Japanese managers more motivated than American managers? A randomly selected group of each were administered the Sarnoff Survey of Attitudes Toward Life (SSATL), which measures motivation for upward mobility. The SSATL scores are summarized below. REF QUIZ 10 #6 Table 10-1 Referring to Table 10-1, give the null and alternative hypotheses to determine if the mean SSATL score of Japanese managers differs from the mean SSATL score of American managers. |
H0: uA - uJ = 0 versus H1: uA -u J =/ 0
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TABLE 10-1
Are Japanese managers more motivated than American managers? A randomly selected group of each were administered the Sarnoff Survey of Attitudes Toward Life (SSATL), which measures motivation for upward mobility. The SSATL scores are summarized below. REF QUIZ 10 #7 Table 10-1 Referring to Table 10-1, what is the value of the test statistic? |
-11.8092
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TABLE 10-1
Are Japanese managers more motivated than American managers? A randomly selected group of each were administered the Sarnoff Survey of Attitudes Toward Life (SSATL), which measures motivation for upward mobility. The SSATL scores are summarized below. REF QUIZ 10 #8 Table 10-1 Referring to Table 10-1, find the p-value if we assume that the alternative hypothesis was a two-tail test. |
Smaller than 0.01
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TABLE 10-3
A real estate company is interested in testing whether the mean time that families in Gotham have been living in their current homes is less than families in Metropolis. Assume that the two population variances are equal. A random sample of 100 families from Gotham and a random sample of 150 families in Metropolis yield the following data on length of residence in current homes. REF QUIZ 10 #9 Table 10-3 Referring to Table 10-3, which of the following represents the relevant hypotheses tested by the real estate company? |
H0: uG - uM >= 0 versus H1: uG - uM < 0
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In what type of test is the variable of interest the difference between the values of the observations rather than the observations themselves?
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A test for the difference between the means of 2 related populations
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In testing for differences between the means of two related populations, the null hypothesis is
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H0: uD = 0.
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A researcher is curious about the effect of sleep on students' test performances. He chooses 60 students and gives each two tests: one given after two hours' sleep and one after eight hours' sleep. The test the researcher should use would be a related samples test.
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True
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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. REF QUIZ 10 #13 Table 10-7 Referring to Table 10-7, the test to perform is a Answer |
paired t test for the mean difference.
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Moving companies are required by the government to publish a Carrier Performance Report each year. One of the descriptive statistics they must include is the annual percentage of shipments on which a $50 or greater claim for loss or damage was filed. Suppose two companies, Econo-Move and On-the-Move, each decide to estimate this figure by sampling their records, and they report the data shown in the following table.
REF QUIZ 10 #14 The owner of On-the-Move is hoping to use these data to show that the company is superior to Econo-Move with regard to the percentage of claims filed. Which test would be used to properly analyze the data in this experiment? |
Z test for the difference between two proportions
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The Wall Street Journal recently published an article indicating differences in perception of sexual harassment on the job between men and women. The article claimed that women perceived the problem to be much more prevalent than did men. One question asked of both men and women was: "Do you think sexual harassment is a major problem in the American workplace?" 24% of the men compared to 62% of the women responded "Yes." Assuming W designates women's responses and M designates men's, what hypothesis should The Wall Street Journal test in order to show that its claim is true?
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H0: nW - nM <= 0 versus H1: nW - nM > 0
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