1. The expression used to compute an interval estimate of m may depend on any of the following factors except
2. The expected value of the random variable is?
3 .In a sample of 800 students in a university, 160, or 20%, are Business majors. Based on the above information, the school's paper reported that "20% of all the students at the university are Business majors." This report is an example of ?
4. A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken. You are given the following information.
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Today
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Five Years Ago
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X'
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82
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88
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s2
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112.5
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54
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n
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45
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36
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The 95% confidence interval for the difference between the two population means is ?
5. In regression analysis, the variable that is being predicted is the
6. Compared to the confidence interval estimate for a particular value of y (in a linear regression model), the interval estimate for an average value of y will be
7. A population consists of 8 items. The number of different simple random samples of size 3 (without replacement) that can be selected from this population is
8. A numerical measure from a sample, such as a sample mean, is known as
9. A tabular summary of data showing the percentage of items in each of several nonoverlapping classes is a
10. In a questionnaire, respondents are asked to record their age in years. Age is an example of a
11. A local department store is studying the shopping habits of its customers. They think that the longer customers spend in the store the more they buy. Their study resulted in the following information regarding the amount of time women and men spent in a store.
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Women
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Men
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Mean
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6 minutes 12 seconds
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5 minutes 46 seconds
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Population Standard deviation
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4 seconds
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5 seconds
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Sample size
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32
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50
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At 95% confidence, what is the conclusion for this study?
12. The birth weight of newborns, measured in grams, is an example of
13. A random sample of 81 automobiles traveling on a section of an interstate showed an average speed of 60 mph. The distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 13.5 mph.
Refer to Exhibit 8-3. If the sample size was 25 (other factors remain unchanged), the interval form would
14. A sample of five Fortune 500 companies showed the following revenues ($ millions): 7505.0, 2904.7, 7208.4, 6819.0, and 19500.0. Based on this information, which of the following statements is correct?
15.
You are given the following information about y and x.
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y
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x
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Dependent
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Independent
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Variable
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Variable
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5
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15
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7
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12
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9
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10
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11
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7
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The least squares estimate of b0 equals
16.
Information on the type of industry is provided for a sample of 50 Fortune 500 companies.
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Industry Type
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Frequency
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Banking
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7
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Consumer Products
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15
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Electronics
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10
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Retail
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18
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The relative frequency of industries that are classified as banking