Name Chapter Three in-class Exercises MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The table below lists the populations, in thousands, of several rural western counties. What is the median population? 1) County Population (thousands) Aldridge 13 Cleveland 10 McCarthy 16 Pope 20 Sorrell 15 Wilson 25 A) 17.5 thousand B) 15 thousand C) 15.5 thousand D) 16.5 thousand 2) Find the sample standard deviation for the following data set: 2) 25 23 17 16 30 A) 5.8 B) 27 C) 33.7 D) 5.2 3) The completion times for a certain marathon race was 2.9 hours with a standard deviation of 0.5 hours. What can you determine about these data by using Chebyshev's Inequality with K = 3? A) At least 88.9% of the completion times are between 1.4 hours and 4.4 hours. B) At most 75% of the completion times are between 1.4 hours and 4.4 hours. C) At least 75% of the completion times are between 1.4 hours and 4.4 hours. D) No more than 88.9% of the completion times are between 1.4 hours and 4.4 hours. 4) For the data set below, find the first quartile. 3) 4) A) 76 B) 43.5 C) 63 D) 61 1
5) A population has a mean μ = 55 and standard deviation σ = 9. What number has a z-score of -0.5? A) -6.2 B) -4.5 C) 50.5 D) -59.5 6) Find the sample variance for the following data set: 5) 6) 22 12 23 17 21 A) 4.5 B) 16.4 C) 11 D) 20.5 Solve the problem. 7) A townʹs snowfall in December averages 19 inches with a standard deviation of 8 inches while in February, the average snowfall is 43 inches with a standard deviation of 14 inches. In which month is it more likely to snow 32 inches? Explain. A) December. Snowfall of 32 inches is - 11 13 from the mean while snowfall of 32 inches is 14 8 from the mean in February. B) February. Snowfall of 32 inches is 13 11 from the mean while snowfall of 32 inches is - 8 14 from the mean in December. C) It is equally likely in either month. One canʹt predict Mother Nature. D) February. Snowfall of 32 inches is - 11 13 from the mean while snowfall of 32 inches is 14 8 from the mean in December. E) December. Snowfall of 32 inches is 13 11 from the mean while snowfall of 32 inches is - 8 14 from the mean in February. 7) 8) The mean weight of babies born in Central hospital last year was 6.3 pounds. Suppose the standard deviation of the weights is 2.1 pounds. Which would be more unusual, a baby weighing 4 pounds or a baby weighing 8.5 pounds? Explain. A) A 4 pound baby is more unusual (z = -1.05) compared with an 8.5 pound baby (z = -1.10). B) An 8.5 pound baby is more unusual (z = -1.10) compared with a 4 pound baby (z = -1.05). C) An 8.5 pound baby is more unusual (z = 1.90) compared with a 4 pound baby (z = 4.05). D) A 4 pound baby is more unusual (z = -1.10) compared with an 8.5 pound baby (z = 1.05). E) An 8.5 pound baby is more unusual (z = -1.05) compared with a 4 pound baby (z = -1.10). 9) A data set has a median of 41, and four of the numbers in the data set are less than median. The data set contains a total of n numbers. 8) 9) If n is odd, and exactly one number in the data set is equal to 41, what is the value of n? A)9 B)12 C)11 D)13 2
10) Gina and Stewart are surf-fishing on the Atlantic coast, where both bluefish and pompano are common catches. The mean length of a bluefish is 261 millimeters with a standard deviation of 45 mm. For pompano, the mean is 156 mm with a standard deviation of 24 mm. 10) Stewart caught a bluefish that was 286 mm long, and Gina caught a pompano that was 181 mm long. Who caught the longer fish, relative to fish of the same species? A) Neither. Relative to its respective species, the fish are the same length. B) Stewart C) Gina 11) The following population parameters were obtained from a graphing calculator. 11) x=66 x=858 x 2 =56628 Sx=6.244998 σx=6 n=13 Assuming the population is bell-shaped, between what two values will approximately 68% of the population be? A) 54 to 78 B) 60 to 72 C) 48 to 84 D) 66 to 84 12) The following population parameters were obtained from a graphing calculator. 12) x=55 x=935 x 2 =51425 Sx=12.3693169 σx=12 n=17 Assuming the population is bell-shaped, approximately what percentage of the populatio values are between 43 and 67? A) 32% B) 68% C) almost all (greater than 95%) D) 95% 3
13) Find the mean for the following data set: 13) 28 14 25 19 20 A) 20 B) 4.9 C) 21.2 D) 14 14) Following are the closing prices (in dollars) of a certain stock for the past 20 trading days. 14) 144.91 153.43 137.98 127.04 120.44 135.94 152.52 144.76 134.82 132.05 146.80 149.61 141.49 126.81 131.42 147.58 127.79 133.94 142.55 138.37 Find the population standard deviation for the closing prices. A) $138.51 B) $9.06 C) $9.30 D) $32.99 15) A population has a mean μ = 21 and standard deviation σ = 4. Find the z-score for a population value of 29. A) 7.3 B) 0.5 C) 8 D) 2 16) For the data set below, find the IQR. 15) 16) A) 65 B) 19 C) 74 D) 9 17) Following are heights, in inches, for a sample of college basketball players. 17) 76 82 83 83 80 83 81 76 78 81 82 82 79 80 77 80 79 76 76 81 Find the mean height of the basketball players. A) 79.5 inches B) 6 inches C) 79.8 inches D) 70 inches 18) For the data set below, find the outlier(s). 18) A) 134 B) 206 C) 204 and 206 D) None are outliers. 4
19) The following data represent the total price, in dollars, of 20 randomly-selected gasoline purchases at a certain convenience store. 19) Find the median price for these purchases. A) $37.40 B) $130.84 C) $35.88 D) $41.88 Find the number of standard deviations from the mean. Round to the nearest hundredths. 20) The average number of average number of hours per day a college student spends on homework is 6 hours with a standard deviation of 0.75 hours. How many standard deviations from the mean is 2 hours spent on homework? A) About 5.33 standard deviations below the mean B) About 5.33 standard deviations above the mean C) About 2.67 standard deviations above the mean D) About 3.00 standard deviations above the mean E) About 2.67 standard deviations below the mean 21) Use the given frequency distribution to approximate the mean. 20) 21) Class Frequency 0 9 8 10 19 18 20 29 12 30 39 11 40 49 17 A) 13.9 B) 26.7 C) 13.2 D) 14 Draw the Normal model and use the 68-95-99.7 Rule to answer the question. 22) The systolic blood pressure of 18-year-old women is normally distributed with a mean of 120 mm Hg and a standard deviation of 12 mm Hg. Draw and label the Normal model for systolic blood pressure. What percentage of 18-year-old women have a systolic blood pressure between 96 mm Hg and 144 mm Hg? A) 22) Blood Pressure (mm Hg) ; 95% 5
B) C) Blood Pressure (mm Hg) ; 99.7% D) Blood Pressure (mm Hg) ; 34% E) Blood Pressure (mm Hg) ; 84% Blood Pressure (mm Hg) ; 68% 23) For which of the following histograms is it appropriate to use the Empirical Rule? A) 23) 6
B) C) D) all of these 24) Find the median for the following data set: 24) 24 18 17 13 25 A) 18 B) 4.5 C) 19.4 D) 12 25) A soft-drink bottling company fills and ships soda in plastic bottles with a target volume of 354 milliliters. The filling machinery does not deliver a perfectly consistent volume of liquid to each bottle, and the three quartiles for the fill volume are Q1 = 347, Q2 = 351, and Q3 = 356. 25) Find the IQR. A) 5 B) 10.8 C) 13.5 D) 9 7
Use summary statistics to answer the question. 26) Here are the summary statistics for the monthly payroll for an accounting firm: lowest salary = $15,000, mean salary = $35,000, median = $25,000, range = $60,000, IQR = $30,000, first quartile = $17,500, standard deviation = $20,000. 26) Between what two values are the middle 50% of the salaries found? A) $15,000 and $75,000 B) $17,500 and $30,000 C) $17,500 and $47,500 D) $17,500 and $37,500 E) $35,000 and $25,000 27) A paint manufacturer discovers that the mean volume of paint in a gallon-sized pail is 1 gallon with a standard deviation of 0.05 gallons. The paint volumes are approximately bell-shaped. Estimate the percent of pails with volumes between 0.90 gallons and 1.10 gallons. A) 5% B) 68% C) almost all (greater than 95%) D) 95% 27) 8
Answer Key Testname: CHAPTER THREE INCLASS EXERCISES 1) C 2) A 3) A 4) C 5) C 6) D 7) D 8) D 9) A 10) C 11) B 12) B 13) C 14) B 15) D 16) D 17) C 18) C 19) D 20) A 21) B 22) A 23) B 24) A 25) D 26) C 27) D 9