Riverside City College



Statistics / Exam 2 Preparation / Ch. 3,4 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.The heights of ten female students (in inches) in a college math class are listed below. Find the mean.65 66 67 66 67 70 67 70 71 68A) 67.7 inches B) 65.5 inches C) 71.1 inches D) 70.0 inchesThe repair costs for five cars which were crashed by a safety testing organization were as follows: $130, $140, $190, $230, and $140. Find the mean cost of repair.A) $166 B) $186 C) $156 D) $176Each year advertisers spend billions of dollars purchasing commercial time on network sports television. In the first 6 months of 1988, advertisers spent $1.1 billion. A recent article listed the top 10 leading spenders (in millions of dollars):Company A $71 Company B $24.9 Company C $ 61.9 Company D $24.4 Company E $56.6 Company F $23 Company G $56.3 Company H $22.5 Company K $29.2 Company J $20.3Calculate the mean amount spent.A) 39.01 million dollars B) 19.84 million dollars C) 393.71 million dollars D) 50.70 million dollarsThe number of students enrolled in a physics class for the last ten semesters are listed below. Find the median number of students.65 66 67 66 67 70 67 70 71 68A) 67 students B) 66 students C) 68 students D) 70 studentsThe median of a data set for a variable is the data value thatA) Lies in the middle of the data when the data is arranged in ascending order.B) Appears the most oftenC) Is the average, that is, the sum of all the data values of the variable divided by the number of observations in the data set?D) None of theseThe following data represents a random sample of 15 complaints registered with the customer service department of a store. Determine the median complaint.Other defective product excessive waiting timeMessy store other otherMessy store other messy storeOther messy store messy storeDefective product other messy storeA) No median B) Messy storeC) Defective product D) Excessive waiting timeThe distribution of salaries of professional basketball players is skewed to the right. Which measure of central tendency would be the best measure to determine the location of the center of the distribution?A) median B) mode C) mean D) frequencyIf the graph of a distribution of data shows that the graph is skewed to the left then theA) Median > MeanB) Mean . MedianC) Mean > MedianD) No conclusion about the relative position of the mean and the median can be madeThe commuting times of ten employees (in minutes) are listed below. Find the mode score.65 66 67 66 67 70 67 70 71 68A) 67 minutes B) 65 minutes C) 66 minutes D) 68 minutesCompute the range for the set of data. 6, 7, 8, 9, 10A) 4 B) 10 C) 0.8 D) 6 Compute the range for the set of data. 15, 17, 15, 17, 15, 17, 15, 17A) 2 B) 17 C) 16 D) 4The book cost (in dollars) for one semester's books are given below for a sample of five college students. Calculate the sample variance of the book costs.280, 120, 405, 485, 325A) 19,007.50 B) 137.87 C) 365.00 D) 323.00Find the sample standard deviation. 14, 15, 16, 17, 18A) 1.6 B) 2.5 C) 1.3 D) 1.5Find the sample standard deviation 81, 75, 44, 63, 42, 30, 64, 76, 88A) 19.9 B) 17.8 C) 350.2 D) 315.2 The costs (in dollars) of 10 college math textbooks are listed below. Find the sample standard deviation. 70 72 71 70 69 73 69 68 70 71$1.49 B) $70.30 C) $5.00 D) $2.23 The scores from a state standardized test have a mean of 80 and a standard deviation of 10. The distribution of the scores is roughly bell shaped. Use the Empirical Rule to find the percentage of scores that lie between 60 and 80.A) 47.5% B) 68% C) 34% D) 95% Fill in the blank. ____________ gives us a method of interpreting the standard deviation that applies to any data set, regardless of the shape of the distribution.A) Chebyshev’s rule B) The Empirical RuleC) Chebyshev’s rule and the empirical rule D) none of these For the following data, approximate the mean number of emails received per day.Emails (per day) Frequency8-11 1512-15 3816-19 1720-23 3124-27 46A) 19.0 B) 18.5 C) 17.5 D) 20.5A student receives test scores of 62, 83, and 91. The student’s term project score is 88 and her homework score is 76. Each test is worth 20% of the final grade, the term project is 25% of the final grade, and the homework grade is 15% of the final grade. What is the student’s mean score in the class?A) 80.6 B) 76.6 C) 83.3 D) 80.0For the following data set, approximate the sample standard deviation of emails per day.Emails (per day) Frequency8-11 1812-15 2316-19 3820-23 4724-27 32A) 5.1 emails B) 4.0 emails C) 25.8 emails D) 19.3 emailsA television station claims that the amount of advertising per hour of broadcast time has an average of 17 minutes and a standard deviation equal to 2.2 minutes. You watch the station for 1 hour, at a randomly selected time, and carefully observe that the amount of advertising time is equal to 7 minutes. Calculate the z-score for this amount of advertising time.A) z = -4.55 B) z = 4.55 C) z = -0.28 D) z = 0.28Construct a scatter diagram for the given data. Determine whether there is a positive linear correlation, negative linear correlation, or no linear correlation.x-5-341-1-2023-4y116-6-1341-4-58Answer: There appears to be a negative linear correlation.A researcher determines that the linear correlation coefficient is 0.85 for a paired data set. This indicates that there isA) a strong positive linear correlation. B) a strong negative linear correlation.C) no linear correlation but that there may be some other relationship.D) insufficient evidence to make any decision about the correlation of the data.A history instructor has given the same pretest and the same final examination each semester. He is interested in determining if there is a relationship between the scores of the two tests. He computes the linear correlation coefficient and notes that it is 1.15. What does this correlation coefficient value tell the instructor?A) The history instructor has made a computational error.B) There is a strong positive correlation between the tests.C) There is a strong negative correlation between the tests.D) The correlation is something other than linear.Calculate the linear correlation coefficient for the data below.x0296435781y17120591072114-0.995 B) -0.671 C) -0.778 D) -0.885A manager wishes to determine whether there is a relationship between the number of years her sales representatives have been with the company and their average monthly sales. The table shows the years of service for each of her sales representatives and their average monthly sales (in thousands of dollars).Years with company, x 4 5 12 9 10 17 5 3 13Sales, y 21 23 68 52 55 51 38 45 110A) r = 0.632; no linear relation exists B) r = 0.632; linear relation existsC) r = 0.717; linear relation exists D) r = 0.717; no linear relation existsFind the equation of the regression line for the given data.x-5-341-1-2023-4y-10-891-2-6-136-8A)= 2.097x - 0.552 B) = 0.522x - 2.097 C) = 2.097x + 0.552 D) = -0.552x + 2.097A residual is the difference betweenA) the observed value of y and the predicted value of y.B) the observed value of x and the predicted value of x.C) the observed value of y and the predicted value of x.D) the observed value of x and the predicted value of y.Use the regression equation to predict the value of y for x = -1.5.x-5-341-1-2023-4y-10-891-2-6-136-8-3.697 B) -2.593 C) 2.925 D) 1.26913) The coefficient of correlation between x and y is r = 0.59. Calculate the coefficient of determination R?.A) 0.35 B) 0.59 C) 0.41 D) 0.65 ................
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