Question 8 A measure of the strength of the relationship between two variables is the Answer coefficient of determination slope b1 of the estimated regression line standard error of the estimate correlation coefficient Question 9 When the data have the properties of interval data and the ratio of two values is meaningful, the variable has which scale of measurement? Answer nominal ordinal interval ratio Question 10 If the cost of a Type I error is high, a smaller value should be chosen for the Answer critical value confidence coefficient level of significance test statistic Question 11 If the data distribution is symmetric, the skewness is Answer 0 .5 1 None of the other answers is correct. Question 12 Exhibit 10-3 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. Today Five Years Ago 82 88 s2 112.5 54 n 45 36 Refer to Exhibit 10-3. The 95% confidence interval for the difference between the two population means is Answer -9.92 to -2.08 -3.92 to 3.92 -13.84 to 1.84 -24.228 to 12.23 Question 13 Exhibit 3-2 A researcher has collected the following sample data. The mean of the sample is 5. 3 5 12 3 2 Refer to Exhibit 3-2. The interquartile range is Answer 1 2 10 12 Question 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? Answer An estimate of the average revenue for all Fortune 500 companies is 8787.42 ($ millions). The average revenue for all Fortune 500 companies is 8787.42 ($ millions). Over half of all Fortune 500 companies earn at least 7208.4 ($ millions) in revenues. If five other Fortune 500 companies were chosen, the average revenue would be 8787.42 ($ millions). Question 15 For the standard normal probability distribution, the area to the left of the mean is Answer -0.5 0.5 any value between 0 to 1 1 Question 16 For any continuous random variable, the probability that the random variable takes on exactly a specific value is Answer 1.00 0.50 any value between 0 to 1 zero Question 17 Excel’s __________ can be used to construct a frequency distribution for qualitative data. Answer DISTRIBUTION function SUM function FREQUENCY function COUNTIF function Question 18 Excel’s NORMSINV function can be used to compute Answer cumulative probabilities for a standard normal z value the standard normal z value given a cumulative probability cumulative probabilities for a normally distributed x value the normally distributed x value given a cumulative probability Question 19 The interquartile range is the difference between the Answer first and second quartiles first and third quartiles second and third quartiles second and fourth quartiles Question 20 Independent simple random samples are taken to test the difference between the means of two populations whose variances are not known. The sample sizes are n1 = 32 and n2 = 40. The correct distribution to use is the Answer binomial distribution t distribution with 72 degrees of freedom t distribution with 71 degrees of freedom t distribution with 70 degrees of freedom Question 21 Which of the following is an example of qualitative data? Answer social security number score on a multiple-choice exam height, in meters, of a diving board number of square feet of carpet Question 22 A frequency distribution is Answer a tabular summary of a set of data showing the fraction of items in each of several nonoverlapping classes a graphical form of representing data a tabular summary of a set of data showing the number of items in each of several nonoverlapping classes a graphical device for presenting categorical data Question 23 A tabular summary of a set of data showing the fraction of the total number of items in several nonoverlapping classes is a Answer frequency distribution. relative frequency distribution. frequency. cumulative frequency distribution. Question 24 Exhibit 2-3 The number of sick days taken (per month) by 200 factory workers is summarized below. Number of Days Frequency 0 – 5 120 6 – 10 65 11 – 15 14 16 – 20 1 Refer to Exhibit 2-3. The number of workers who took more than 10 sick days per month Answer was 15 was 200 was 185 was 65 Question 25 A graphical presentation of a frequency distribution, relative frequency distribution, or percent frequency distribution of quantitative data constructed by placing the class intervals on the horizontal axis and the frequencies on the vertical axis is a Answer histogram bar graph stem-and-leaf display pie chart Question 26 The sample statistic s is the point estimator of Answer m