Section 1

Multiple Choice Questions

1. If unemployment is 5.5% of the population, what is this level of measurement?
A) Nominal
B) Ordinal
C) Interval or ratio
D) Descriptive
E) None of the above

2. A student was interested in the cigarette smoking habits of college students and collected data from an unbiased random sample of students. The data is summarized in the following table:

Why is the table NOT a frequency distribution?
A) The number of males does not equal the sum of males that smoke and do not smoke.
B) The classes are not mutually exclusive.
C) There are too many classes.
D) Class limits cannot be computed

3. A row of a stem-and-leaf chart appears as follows: 3 | 0 1 3 5 7 9. Assume that the data is rounded to the nearest unit.
A) The frequency of the class is seven.
B) The minimum value in the class is 0.
C) The maximum value in the class could be 39.
D) The class interval is 5.

Refer to the following chart showing a distribution of exporting firms to answer questions 11-13:

4. What is the relative frequency of those salespersons that earn more than $1,599?
A) 25.5%
B) 27.5%
C) 29.5%
D) 30.8%
E) None of the above

5. For the distribution above, what is the midpoint of the class with the greatest frequency?
A) $ 6 million
B) $ 9.5 million
C) $ 15.5 million
D) The midpoint cannot be determined
E) None of the above

6. What is the class interval? _____
A) 2
B) 3
C) 3.5
D) 4
E) None of the above

7. Which measures of central tendency are not affected by extremely low or extremely high values?
A) Mean and median
B) Mean and mode
C) Mode and median
D) Geometric mean and mean
E) None of the above

8. If there is an odd number of observations in a set of ungrouped data that have been arrayed from low to high or vice versa, where is the median located?
A) n
B) n/2
C) (n + 1)/2
D) n + 1/2
E) None of the above.

9. The net incomes (in $ millions) of a sample of steel fabricators are: $86, $67, $86 and $85. What is the modal net income?
A) $67
B) $85
C) $85.5
D) $86
E) None of the above

10. A purchasing agent for a trucking company is shopping for replacement tires for their trucks from two suppliers. The suppliers’ prices are the same. However, Supplier A’s tires have an average life of 60,000 miles with a standard deviation of 10,000 miles. Supplier B’s tires have an average life of 60,000 miles with a standard deviation of 2,000 miles. Which of the following statements is true?
A) The two distributions of tire life are the same
B) On average, Supplier A’s tires have a longer life then Supplier B’s tires
C) The life of Supplier B’s tire is more predictable than the life of Supplier A’s tires
D) The dispersion of Supplier A’s tire life is less than the dispersion of Supplier B’s tire life

11. What statistics are needed to draw a box plot?
A) Minimum, maximum, median, first and third quartiles
B) Median, mean and standard deviation
C) A mean and a dispersion
D) A mean and a standard deviation

12. Which of the following measures of dispersion are based on deviations from the mean?
A) Variance
B) Standard deviation
C) Mean deviation
D) All of the above
E) None of the above

13. What do the quartile deviation and the interquartile range describe?
A) Lower 50% of the observations
B) Middle 50% of the observations
C) Upper 50% of the observations
D) Lower 25% and the upper 25% of the observations
E) None of the above

14. What is the relationship between the variance and the standard deviation?
A) Variance is the square root of the standard deviation
B) Variance is the square of the standard deviation
C) Variance is twice the standard deviation
D) No constant relationship between the variance and the standard deviation
E) None of the above.

15. Mr. and Mrs. Jones live in a neighborhood where the mean family income is $45,000 with a standard deviation of $9,000. Mr. and Mrs. Smith live in a neighborhood where the mean is $100,000 and the standard deviation is $30,000. What are the relative dispersion of the family incomes in the two neighborhoods?
A) Jones 40%, Smith 20%
B) Jones 20%, Smith 30%
C) Jones 30%, Smith 20%
D) Jones 50%, Smith 33%
E) None of the above

16. According to Chebyshev’s Theorem, what percent of the observations lie within plus and minus 1.75 standard deviations of the mean?
A) 56%
B) 95%
C) 67%
D) Cannot compute because it depends on the shape of the distribution
E) None of the above

17. A large oil company is studying the number of gallons of gasoline purchased per customer at self-service pumps. The mean number of gallons is 10.0 with a standard deviation of 3.0 gallons. The median is 10.75 gallons. What is the Pearson’s coefficient of skewness?
A) -1.00
B) -0.75
C) +0.75
D) +1.00
E) None of the above

18. What is the range for a sample of March electric bills amounts for all-electric homes of similar sizes (to the nearest dollar): $212, $191, $176, $129, $106, $92, $108, $109, $103, $121, $175 and $194.
A) $100
B) $130
C) $120
D) $112
E) None of the above

19. The weights (in kilograms) of a group of crates being shipped to Panama are 95, 103, 110, 104, 105, 112 and 92. What is the mean deviation?
A) 5.43 kg
B) 6.25 kg
C) 0.53 kg
D) 52.50 kg
E) None of the above

20. A sample of the monthly amounts spent for food by families of four receiving food stamps approximates a symmetrical distribution. The sample mean is $150 and the standard deviation is $20. Using the Empirical Rule, about 95 percent of the monthly food expenditures are between what two amounts?
A) $100 and $200
B) $85 and $105
C) $205 and $220
D) $110 and $190
E) None of the above

21. The ages of all the patients in the isolation ward of the hospital are 38, 26, 13, 41 and 22. What is the population variance?
A) 106.8
B) 91.4
C) 240.3
D) 42.4
E) None of the above

22. If the sample variance for a frequency distribution consisting of hourly wages was computed to be 10, what is the sample standard deviation?
A) $1.96
B) $4.67
C) $3.16
D) $10.00
E) None of the above

23. If two events A and B are mutually exclusive,What does the complement rule state?
A) P(A) = P(A) – P(B)
B) P(A) = 1 – P(not A)
C) P(A) = P(A)• P(B)
D) P(A) = P(A)X + P(B)
E) None of the above.

24. What type of variable is the number of gallons of gasoline pumped by a filling station during a day?
A. Qualitative
B. Continuous
C. Attribute
D. Discrete
25. Routine physical examinations are conducted annually as part of a health service program for the employees. It was discovered that 8% of the employees needed corrective shoes, 15% needed major dental work and 3% needed both corrective shoes and major dental work. What is the probability that an employee selected at random will need either corrective shoes or major dental work?
A) 0.20
B) 0.25
C) 0.50
D) 1.00
E) None of the above

26. A tire manufacturer advertises, “the median life of our new all-season radial tire is 50,000 miles. An immediate adjustment will be made on any tire that does not last 50,000 miles.” You purchased four of these tires. What is the probability that all four tires will wear out before traveling 50,000 miles?
A) 1/10, or 0.10
B) ¼, or 0.25
C) 1/64, or 0.0156
D) 1/16, or 0.0625
E) None of the above

27. There are 10 rolls of film in a box and 3 are defective. Two rolls are to be selected, one after the other. What is the probability of selecting a defective roll followed by another defective roll?
A) 1/2, or 0.50
B) 1/4, or 0.25
C) 1/120, or about 0.0083
D) 1/15, or about 0.07
E) None of the above

28. A board of directors consists of eight men and four women. A four-member search committee is to be chosen at random to recommend a new company president. What is the probability that all four members of the search committee will be women?
A) 1/120 or 0.00083
B) 1/16 or 0.0625
C) 1/8 or 0.125
D) 1/495 or 0.002
E) None of the above
29. Consideration is being given to forming a Super Ten Football Conference. The top 10 football teams in the country, based on past records, would be members of the Super Ten Conference. Each team would play every other team in the conference during the season and the team winning the most games would be declared the national champion. How many games would the conference commissioner have to schedule each year? (Remember, Oklahoma versus Michigan is the same as Michigan versus Oklahoma.)
A) 45
B) 50
C) 125
D) 14
E) None of the above

30. When are two events mutually exclusive?
A) They overlap on a Venn diagram
B) If one event occurs, then the other cannot
C) Probability of one affects the probability of the other
D) Both (a) and (b)

31. A visual means useful in calculating joint and conditional probability is
A) a tree diagram.
B) a Venn diagram.
C) a histogram.
D) inferential statistics.
E) none of the above.

32. When an experiment is conducted “without replacement”,
A) events are independent
B) events are equally likely
C) the experiment can be illustrated with a Venn Diagram
D) the probability of two or more events is computed as a joint probability

33. Which of the following is an example of attribute data?
A. Number of children in a family
B. Weight of a person
C. Color of ink in a pen
D. Miles between oil changes
34. What is the following table called?

A. Histogram
B. Frequency polygon
C. Cumulative frequency distribution
D. Frequency distribution
35. Refer to the following distribution of commissions:

What is the class interval?
A. 200
B. 300
C. 3.500
36. In a contingency table, we describe the relationship between
A. two variables measured at the ordinal or nominal level.
B. two variables, one measured as an ordinal variable and the other as a ratio variable.
C. two variables measured at the interval or ratio level.
D. a variable measure on the interval or ratio level and time.
37. The probabilities and the number of automobiles lined up at a Lakeside Olds at opening time (7:30 a.m.) for service are

On a typical day, how many automobiles should Lakeside Olds expect to be lined up at opening?
A. 10.00
B. 1.00
C. 2.85
D. 1.96
38. Which one of the following is NOT a condition of the binomial distribution?
A. Independent trials
B. Only two outcomes
C. Probability of success remains constant from trial to trial
D. At least 10 observations
39. In a large metropolitan area, past records revealed that 30 percent of all the high school graduates go to college. From 20 graduates selected at random, what is the probability that exactly 8 will go to college?
A. 0.114
B. 0.887
C. 0.400
D. 0.231
40. A farmer who grows genetically engineered corn is experiencing trouble with corn borers. A random check of 5,000 ears revealed the following: many of the ears contained no borers. Some ears had one borer; a few had two borers; and so on. The distribution of the number of borers per ear approximated the Poisson distribution. The farmer counted 3,500 borers in the 5,000 ears. What is the probability that an ear of corn selected at random will contain no borers?
A. 0.3476
B. 0.4966
C. 1.000
D. 0.0631
A company is studying the number of monthly absences among its 125 employees. The following probability distribution shows the likelihood that people were absent 0, 1, 2, 3, 4, or 5 days last month.

41. Given the probability distribution, which of the following predictions is correct?
A. 60% of the employees will have more than one day absent for a month.
B. There is a 0.04 probability that an employee will be absent 1 day during a month.
C. There is a 0.12 probability that an employee will be absent 2 days during a month.
D. There is a 0.50 probability that an employee will be absent 0.72 days during a month.
For the following distribution,

42. What is the variance of the distribution?
A. 1.1616
B. 0.964
C. 0.982
D. 1.000
43. The standard deviation of any uniform probability distribution is
A. (b – a)/2
B. n(1 – )
C.
D.
44. What is an important similarity between the uniform and normal probability distributions?
A. The mean, median and mode are all equal.
B. The mean and median are equal.
C. They are negatively skewed.
D. About 68% of all observations are within one standard deviation of the mean.
45. What is an important similarity between the uniform and normal probability distributions?
A. The mean, median and mode are all equal.
B. The mean and median are equal.
C. They are negatively skewed.
D. About 68% of all observations are within one standard deviation of the mean.
46. The mean amount spent by a family of four on food per month is $500 with a standard deviation of $75. Assuming that the food costs are normally distributed, what is the probability that a family spends less than $410 per month?
A. 0.2158
B. 0.8750
C. 0.0362
D. 0.1151

47. Which of the following is NOT a characteristic of the normal probability distribution?
A. Positively-skewed
B. Bell-shaped
C. Symmetrical
D. Asymptotic
48. The mean of a normally distributed group of weekly incomes of a large group of executives is $1,000 and the standard deviation is $100. What is the z-score for an income of $1,100?
A. 1.00
B. 2.00
C. 1.683
D. -0.90
49. A new extended-life light bulb has an average service life of 750 hours, with a standard deviation of 50 hours. If the service life of these light bulbs approximates a normal distribution, about what percent of the distribution will be between 600 hours and 900 hours?
A. 95%
B. 68%
C. 34%
D. 99.7%
50. An accelerated life test on a large number of type-D alkaline batteries revealed that the mean life for a particular use before they failed is 19.0 hours. The distribution of the lives approximated a normal distribution. The standard deviation of the distribution was 1.2 hours. About 95.44 percent of the batteries failed between what two values?
A. 8.9 and 18.9
B. 12.2 and 14.2
C. 14.1 and 22.1
D. 16.6 and 21.4
51. Tables of normal distribution probabilities are found in many statistics books. These probabilities are calculated from a normal distribution with
A. a mean of 1 and a standard deviation of 1
B. a mean of 100 and a standard deviation of 15
C. a mean of 0 and a standard deviation of 15
D. a mean of 0 and a standard deviation of 1

52. Two normal distributions are compared. One has a mean of 10 and a standard deviation of 10. The second normal distribution has a mean of 10 and a standard deviation of 2. Which of the following is true?
A. The locations of the distributions are different
B. The distributions are from two different families of distributions
C. The dispersions of the distributions are different
D. The dispersions of the distributions are the same
53. The weight of cans of fruit is normally distributed with a mean of 1,000 grams and a standard deviation of 50 grams. What percent of the cans weigh 860 grams or less?
A. 0.0100
B. 0.8400
C. 0.0026
D. 0.0001
54. What is a normal distribution with a mean of 0 and a standard deviation of 1 called?
A. Frequency distribution
B. Z-score
C. Standard normal distribution
D. Binomial probability distribution
55. A large manufacturing firm tests job applicants who recently graduated from college. The test scores are normally distributed with a mean of 500 and a standard deviation of 50. Management is considering placing a new hire in an upper level management position if the person scores in the upper 6 percent of the distribution. What is the lowest score a college graduate must earn to qualify for a responsible position?
A. 50
B. 625
C. 460
D. 578
56. An analysis of the grades on the first test in History 101 revealed that they approximate a normal curve with a mean of 75 and a standard deviation of 8. The instructor wants to award the grade of A to the upper 10 percent of the test grades. What is the dividing point between an A and a B grade?
A. 80
B. 85
C. 90
D. 95
57. The mean of a normal probability distribution is 500 and the standard deviation is 10. About 95 percent of the observations lie between what two values?
A. 475 and 525
B. 480 and 520
C. 400 and 600
D. 350 and 650
58. Suppose a tire manufacturer wants to set a mileage guarantee on its new XB 70 tire. Tests revealed that the tire’s mileage is normally distributed with a mean of 47,900 miles and a standard deviation of 2,050 miles. The manufacturer wants to set the guaranteed mileage so that no more than 5 percent of the tires will have to be replaced. What guaranteed mileage should the manufacturer announce?
A. 44,528
B. 32,960
C. 49,621
D. 40,922
59. A marketing class of 50 students evaluated the instructor using the following scale: superior, good, average, poor, and inferior. The descriptive summary showed the following survey results: 2% superior, 8% good, 45% average, 45% poor, and 0% inferior.
A. The instructor’s performance was great!!!
B. The instructor’s performance was inferior.
C. Most students rated the instructor as poor or average.
D. No conclusions can be made.
60. Respondents were asked, “Do you now earn more than or less than you did five years ago?” What is this level of measurement?
A. Interval
B. Ratio
C. Nominal
D. Ordinal