STT 231 Test 1 Fill in the Letter of Your Choice to Each Question in the Scantron. Each question is worth 2 point. 1. A professor has kept records on grades that students have earned in his class. If he wants to examine the percentage of students earning the grades A, B, C, D and F during the most recent exam, which kind of plot should he make? A) boxplot B) timeplot C) dotplot D) pie chart E) histogram 2. The mean weight of three gemstones is 20 grams. The weights of two of the stones are 15 grams and 17 grams. What is the weight of the third stone? A) 16 grams B) 10 grams C) 28 grams D) 14 grams E) not enough information to determine the weight of the third stone. 3) Answer C 4. Which one of the following statements below contains no mistake? A) The correlation between height and weight is 0.568 inches per pound B) The correlation between height and weight is 0.568 C) The correlation between the breed of a dog and its weight is 0.568 D) The correlation between gender and age is -0.568 E) If the correlation between blood alcohol level and reaction time is 0.73, then the correlation between reaction time and blood alcohol level is -0.73.
Relative frequency 5. A study is conducted to determine if one can predict the yield of a crop based on the amount of yearly rainfall. The response variable in this study is A) the amount of rainfall B) the crop yield C) the average temperature during the study time D) the researchers who conducted the study Use the following to answer questions 6, 7: A study is being conducted on air quality at a small college in the South. As part of this study, monitors were posted at every entrance to this college from 6 A.M. to 10 P.M. on a randomly chosen day. The monitors recorded the mode of transportation used by each person as they entered the campus. Based on the information recorded, the following bar graph was constructed. 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Car (driver) Bike Car (passenger) Bus Mode of transportation Foot Skateb/Rollerbl. 6.Approximately what percentage of people entering campus on this particular day arrived by car? A)9% B) 31% C) 53% D) 62% 7.If 1200 people entered campus on this particular day, (approximately) how many people arrived by bus? A) 10 B) 100 C) 120 D) 135 8. School administrators collect data on students attending the school. Which of the following variables is quantitative? A) class (freshman, sophomore, junior, senior) B) grade point average C) whether the student is in AP classes D) whether the student has taken SAT
9. The following histogram pictures the number of students who visited the Career Center each week during the school year. The shape of this graph could best be described as A) symmetric B) Bi-modal C) Skewed to the left D) Uniform E) Skewed to the right 10. Which of the following cases use histograms to display information? A) Annual expenses for a family of four on food, mortgage, healthcare, vacation, etc B) GMs car sales by type during the Christmas season (Chevy, Pontiac, Buick, etc) C) IQ cores of all MSU students D) Number of in-state and out-of-state students at MSU 11. A correlation of zero between two quantitative variables means that A) we have done something wrong in our calculation. It is impossible for correlation to be 0. B) there is no association between the two variables C) there is no linear association between the two variables D) re-expressing the data will guarantee a linear association between the two variables 12. In a study of 1991 model cars, a researcher computed the least-squares regression line of price (in dollars) on horsepower. He obtained the following equation for this line. price = 6677 + 175 horsepower. Based on the least-squares regression line, what would we predict the cost of a 1991 model car with horsepower equal to 200 to be? A) $41,677 B) $35,000 C) $28,323 D) $13,354
Use the following for Questions 13,14,15. A survey of college students finds that 40% like country music, 30% like gospel and 10% like both. 13. What percent like neither country nor gospel? (A) 0.10 (B) 0.4 (C) 0.20 (D) 0.25 14. What percent like either country or gospel, but not both? (A) 0.10 (B) 0.4 (C) 0.20 (D) 0.50 15. What percent like gospel only? (A) 0.10 (B) 0.4 (C) 0.20 (D) 0.25 16. Belgium has two official languages French and Dutch. Assume that about 60% of the people speak Dutch and 40% of the people speak French. Define the event A as the event that two randomly selected Belgians speak the same language. What is the complement of event A? A) 0.48 B) 0.52 C) {Dutch, French} D) {(Dutch, French), (French, Dutch)} 17 A national consumer magazine reported the following correlations: The correlation between car weight and car reliability is -0.30 and the correlation between car weight and annual maintenance cost is 0.70. Which of the following statements are true? I. Heavier cars tend to be less reliable II. Heavier cars tend to cost more to maintain. III. Car weight is related more strongly to reliability than to maintenance cost. A) I only B) II only C) III only D) I and II E) I, II and III 18. From a list of registered voters who are Democrats (D), Republicans (R) and Independents (I), 2 voters are randomly selected. The sample space of this experiment is {D, R, I}. A) TRUE B) FALSE
19. The following values are listed as coefficients of correlation (r). Which one indicates a strong negative relationship between the variables x and y? A) -0.05 B) -1.2 C) 0.4 D) 1.1 E) -0.9 Use the following to answer questions 20, 21: If you draw an M&M candy at random from a bag of the candies, the candy you draw will have one of six colors. The probability of drawing each color depends on the proportion of each color among all candies made. Assume the table below gives the probabilities for the color of a randomly chosen M&M. Color Brown Red Yellow Green Orange Blue Probability 0.3 0.3? 0.1 0.1 0.1 20. What is the probability of drawing a yellow candy? A) 0.1 B) 0.2 C) 0.3 D) Impossible to determine from the information given. 21. What is the probability that you draw neither a brown nor a green candy? A) 0.3 B) 0.6 C) 0.7 D) 0.9 22. Foresters use regression to predict the volume of timber in a tree using easily measured quantities such as diameter. Let Y be the volume of timber in cubic feet and X be the diameter in feet (measured at 3 feet above ground level, 1 ft = 12 inches). One set of data gives Y = -30 + 60x. The predicted volume for a tree of diameter = 18inches is A) 1050 cubic feet B) 65 cubic feet C) 90 cubic feet D) 100 cubic feet E) 60 cubic feet
Use the following for Problems 23-25. In a statistics class with 133 students, the professor records how much money each student has in their possession during the first class of the semester. The histogram shown below represents the data he collected. 23. Which of the following is true? A) The histogram is unimodal B) There is no outlier present. C) The histogram is approximately symmetric D) The histogram is skewed left. 24. What is approximately the percentage of students with under $10.00 in their possession? A) 40% B) 45% C) 35% D) 50% 25. What is approximately the number of students with $30.00 or more in their possession? A) Less than 5 B) More than 100 C)About 30 D) About 10