A class survey asked students to indicate if they are MAC or PC users Of the

A class survey asked students to indicate if they are

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41. A class survey asked students to indicate if they are MAC or PC users. Of the followinggraphs, which is most appropriate to display their results? A) HistogramB) Stem-and-leaf displayC) ScatterplotD) Bar ChartE) Boxplot 42. Which of the following table(s) is/are valid distribution for a particular random variable.Table 1x012P(x)0.40.40Table 2y-104P(y)0.120.73.15Table 3z3711P(z)0.280.32.40 43. Which of the following statement(s) about histogram is/are FALSE? I The total area of a histogram equals 1.Question 43 continues on the next page. . .
Page 19 of 25II A histogram can display only one peak.III A histogram is used to describe a categorical variable 44. Which of the following statement(s) about the width of a confidence interval is/areTRUE?I If we increase the sample size n then the width of the confidence interval increases.II The width of a confidence interval equals its margin of errorIII If we increase the confidence-level of a confidence interval then the width of theconfidence interval increases. 45. Use this information for this question and the next question.A telephone companyknows that long distance telephone bills are normally distributed. A random sample of25 customers is selected and the mean bill is $25 with a standard deviation of $12. Whatis a 98% confidence interval for the mean long distance telephone bill? A) 25±6.7128B) 25±5.9808C) 25±5.9640D) 25±6.6888E) 25±1.342646. Refer to the information in question 45. The company says that the mean long distancetelephone bills is $27. A random sample of 25 customers is selected and the mean bill is$25 with a standard deviation of $12. The value of test statistics for testing whether themean long distance telephone bills differs from $27 ist=-0.833. What is the P-valueof this observed test statistics? Question 46 continues on the next page. . .
Page 20 of 25 47. Use this information for this question and the next two questions.According to theunion agreement, the mean income for all senior-level assembly line workers in a largecompany equals $500 per week. A representative of womens group decides to analyzewhether the mean income for female employees differs from $500 per week. She collectsa random sample of nine female employees and finds that the sample mean is $470 andthe sample standard deviation is $90.Assume that the income for female employeeshave a Normal distribution. What should she define as the notations for stating the nulland alternative hypotheses in the context of this study?

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