Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Solve the problem. 1) The volumes of soda in quart soda bottles can be described by a Normal model with a mean of 32.3 oz and a standard deviation of 1.2 oz. What percentage of bottles can we expect to have a volume less than 32 oz? A) 40.13% B) 38.21% C) 47.15% D) 9.87% E) 59.87% 1) 2) A bankʹs loan officer rates applicants for credit. The ratings can be described by a Normal model with a mean of 200 and a standard deviation of 50. If an applicant is randomly selected, what percentage can be expected to be between 200 and 275? A) 5.00% B) 42.37% C) 6.68% D) 43.32% E) 93.32% 2) 3) The lengths of human pregnancies can be described by a Normal model with a mean of 268 days and a standard deviation of 15 days. What percentage can we expect for a pregnancy that will last at least 300 days? A) 1.66% B) 48.34% C) 98.34% D) 1.99% E) 1.79% 3) 4) For a recent English exam, use the Normal model N(73, 9.2) to find the percent of scores over 85. Round to the nearest tenth of a percent. A) 8.1% B) 9.7% C) 90.3% D) 11.5% E) 88.5% 4) Solve the problem. Round to the nearest tenth. 5) For a recent English exam, use the Normal model N(73, 9.2) to find the score that represents the 30th percentile. A) 82.2 B) 77.8 C) 68.2 D) 61.2 E) 63.8 5) 6) Based on the Normal model for snowfall in a certain town N(57, 8), how many inches of snow would represent the 25th percentile? A) 14.3 inches B) 51.6 inches C) 65 inches D) 62.4 inches E) 49 inches 6) 7) Based on the Normal model for car speeds on an old town highway N(77, 9.1), what is the cutoff value for the highest 15% of the speeds? A) about 63.1 mph B) about 86.5 mph C) about 11.6 mph D) about 67.5 mph E) about 65.5 mph 7) 1
8) Based on the Normal model for car speeds on an old town highway N(77, 9.1), what are the cutoff values for the middle 20% of the speeds? A) about 84.7 mph, about 69.3 mph B) about 74.7 mph, about 79.3 mph C) about 86.1 mph, about 67.9 mph D) about 95.2 mph, about 58.8 mph E) about 61.6 mph, about 92.4 mph 8) Suppose you are to form a scatterplot by collecting data for the given pair of variables. Determine the likely direction, form, and strength. 9) Hot chocolate sales, heater sales 9) A) Positive, nonlinear, moderate B) Negative, nonlinear, moderate C) Negative, straight, moderate D) Positive, no form, strong E) Positive, straight, moderate Find the correlation. 10) The paired data below consist of the test scores of 6 randomly selected students and the number of hours they studied for the test. 10) Hours Score 5 64 10 86 4 69 6 86 10 59 9 87 A) -0.678 B) 0.224 C) -0.224 D) 0.678 E) 0.157 11) A study was conducted to compare the average time spent in the lab each week versus course grade for computer students. The results are recorded in the table below. 11) Number of hours spent in lab Grade (percent) 10 96 11 51 16 62 9 58 7 89 15 81 16 46 10 51 A) 0.371 B) 0.462 C) -0.335 D) -0.284 E) 0.017 2
Several scatterplots are given with calculated correlations. Which is which? 12) 1) 2) 12) 3) 4) a) -0.944, b) -0.435, c) 0.004, d) 0.753 A) 1d, 2a, 3b, 4c B) 1c, 2a, 3d, 4c C) 1a, 2b, 3c, 4d D) 1b, 2c, 3d, 4a E) 1c, 2d, 3a, 4b Solve the problem. 13) A science instructor assigns a group of students to investigate the relationship between the ph of the water of a river and its waterʹs hardness (measured in grains). Some students wrote these conclusions: ʺthere was a very strong correlation of 1.45 between ph of the water and waterʹs hardness.ʺ Is the calculation of the correlation appropriate? A) No: correlation cannot be greater than 1. B) Yes: correlation can be greater than 1. C) No: there is little or no association. D) No: correlation must be equal to 1. E) Yes: the ph and the hardness of the water are data collected from the same river. 13) Answer the question appropriately. 14) A golf ball is dropped from 15 different heights (in inches) and the height of the bounce is recorded (in inches.) The regression analysis gives the model bounce = -0.4 + 0.75 drop. Explain what the slope of the line says about the bounce height and the drop height of the ball. A) On average, the drop height increases by 0.75 inches for every extra inch of bounce height. B) On average, the bounce height increases by 0.75 inches for every extra inch of drop height. C) On average, the bounce height will be 0.75 inches less than the drop height. D) On average, the drop height increases by -0.4 inches for every extra inch of bounce height. E) On average, the bounce height increases by -0.4 inches for every extra inch of drop height. 14) 3
15) If you create a regression model for predicting the weight of a motorcycle (in pounds) from its length (in feet), is the slope most likely to be 0.8, 8, 80, 800, or 8000? A) 80 B) 8000 C) 800 D) 0.8 E) 8 15) 16) A random sample of records of electricity usage of homes gives the amount of electricity used and size (in square feet) of 135 homes. A regression to predict the amount of electricity used (in kilowatt-hours) from size has an R-squared of 71.0%. The residuals plot indicated that a linear model is appropriate. Write a sentence summarizing what R2 says about this regression. A) Size differences explain 71.0% of the variation in electricity usage. B) Differences in electricity usage explain 29% of the variation in the number of house. C) Size differences explain 29% of the variation in electricity usage. D) Differences in electricity usage explain 71.0% of the variation in the size of house. E) Size differences explain 71.0% of the variation in the number of homes. 16) Use the model to make the appropriate prediction. 17) A random sample of records of electricity usage of homes in the month of July gives the amount of electricity used and size (in square feet) of 135 homes. A regression was done to predict the amount of electricity used (in kilowatt-hours) from size. The residuals plot indicated that a linear model is appropriate. The model is usage = 1271 + 0.2 size. How much electricity would you predict would be used in a house that is 2471 square feet? A) 494.2 kilowatt-hours B) 3742.2 kilowatt-hours C) 6000.00 kilowatt-hours D) 776.8 kilowatt-hours E) 1765.2 kilowatt-hours 18) A golf ball is dropped from 15 different heights (in inches) and the height of the bounce is recorded (in inches.) The regression analysis gives the model bounce = 0.5 + 0.69 drop. Predict the height of the bounce if dropped from 70 inches. A) 100.72 inches B) 71.19 inches C) 48.8 inches D) 48.3 inches E) 47.8 inches 19) The relationship between the number of games won during one season by a minor league baseball team and the average attendance at their home games is analyzed. A regression analysis to predict the average attendance from the number of games won gives the model attendance = -2600 + 222 wins. Predict the average attendance of a team with 470 wins. Explain any possible problems with this prediction. A) 106,940 people. A team doesnʹt play that many games and their stadiums probably canʹt hold that many people. B) 14 people. There are other factors besides number of games won. C) 7834 people. There is no problem with this prediction. D) 101,740 people. A team doesnʹt play that many games and their stadiums probably canʹt hold that many people. E) 104,340 people. It is only an estimate. 17) 18) 19) 4
Use the given data to find the equation of the regression line. Round to 3 significant digits, if necessary. 20) Ten Ford Escort classified ads were selected. The age and prices of several used Ford Escorts are given in the table. 20) A) price B) price C) price D) price E) price Age (years) Price 1 $10,000 2 $8500 2 $8000 3 $6000 3 $5900 4 $5800 4 $5000 5 $3000 6 $2000 6 $1900 = 7.05-0.000616 age = 7200-692 age = -1580 + 11300 age = 10000-1600 age = 11300-1580 age 21) Two different tests are designed to measure employee productivity and dexterity. Several employees are randomly selected and tested with these results. 21) Dexterity 23 25 28 21 21 25 26 30 34 36 Productivity 49 53 59 42 47 53 55 63 67 75 A) Productivity = 75.3-0.329 Dexterity B) Productivity = 5.05 + 1.91 Dexterity C) Productivity = 10.7 + 1.53 Dexterity D) Productivity = 6.08 + 1.56 Dexterity E) Productivity = 2.36 + 2.03 Dexterity 5
Answer Key Testname: SAMPLE TEST2 1) A 2) D 3) A 4) B 5) C 6) B 7) B 8) B 9) E 10) B 11) C 12) E 13) A 14) B 15) A 16) A 17) E 18) C 19) D 20) E 21) B 6