econ 10

18. In constructing a frequency distribution, the approximate class width is computed as a. (largest data value - smallest data value)/number of classes b. (largest data value - smallest data value)/sample size c. (smallest data value - largest data value)/sample size d. largest data value/number of classes

a. (largest data value - smallest data value)/number of classes

55. If A and B are independent events with P(A) = 0.05 and P(B) = 0.65, then P(A | B) = a. 0.05 b. 0.0325 c. 0.65 d. 0.8

a. 0.05

Forty percent of all registered voters in a national election are female. A random sample of 5 voters is selected. 80. Refer to Exhibit 5-4. The probability that there are no females in the sample is a. 0.0778 b. 0.7780 c. 0.5000 d. 0.3456

a. 0.0778

49. If A and B are independent events with P(A) = 0.65 and P(A ∩ B) = 0.26, then, P(B) = a. 0.400 b. 0.169 c. 0.390 d. 0.650

a. 0.400

The following represents the probability distribution for the daily demand of computers at a local store. Demand Probability 0 0.1 1 0.2 2 0.3 3 0.2 4 0.2 78. Refer to Exhibit 5-1. The probability of having a demand for at least two computers is a. 0.7 b. 0.3 c. 0.4 d. 1.0

a. 0.7

Undergraduate Major Graduate School Business Engineering Others Total Yes 70 84 126 280 No 182 208 130 520 Total 252 292 256 800 24. Refer to Exhibit 2-2. Of those students who are majoring in business, what percentage plans to go to graduate school? a. 27.78 b. 8.75 c. 70 d. 72.22

a. 27.78

63. A student has selected 8 books that she likes, but she has money only for 3 books. How many possible selections does she have? a. 56 b. 240 c. 8 d. 24

a. 56

A researcher is gathering data from four geographical areas designated: South = 1; North = 2; East = 3; West = 4. The designated geographical regions represent a. categorical data b. quantitative data c. label data d. either quantitative or categorical data

a. categorical data

41. In computing descriptive statistics from grouped data, a. data values are treated as if they occur at the midpoint of a class b. the grouped data result is more accurate than the ungrouped result c. the grouped data computations are used only when a population is being analyzed d. None of these alternatives is correct.

a. data valies are treated as if they occur at the midpoint of a class

The random variable x is the number of occurrences of an event over an interval of ten minutes. It can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. It is known that the mean number of occurrences in ten minutes is 5.3. 82. Refer to Exhibit 5-8. The appropriate probability distribution for the random variable is a. discrete b. continuous c. either discrete or continuous depending on how the interval is defined d. None of these alternatives is correct.

a. discrete

67. An experiment consists of making 80 telephone calls in order to sell a particular insurance policy. The random variable in this experiment is a a. discrete random variable b. continuous random variable c. complex random variable d. simplex random variable

a. discrete random variable

The relative frequency of a class is computed by a. dividing the midpoint of the class by the sample size b. dividing the frequency of the class by the midpoint c. dividing the sample size by the frequency of the class d. dividing the frequency of the class by the sample size

a. dividing the mid point of the class by the sample size.

39. When data are positively skewed, the mean will usually be a. greater than the median b. smaller than the median c. equal to the median d. positive

a. greater than the median

The most common graphical presentation of quantitative data is a a. histogram b. bar chart c. relative frequency d. pie chart

a. histogram

27. μ is an example of a a. population parameter b. sample statistic c. population variance d. mode

a. population parameter

40. If the variance of a data set is correctly computed with the formula using n - 1 in the denominator, which of the following is true? a. the data set is a sample b. the data set is a population c. the data set could be either a sample or a population d. the data set is from a census

a. the data set is a sample

The collection of all elements of interest in a particular study is a. the population b. the sampling c. statistical inference d. Data and Statistics

a. the population

The random variable x is the number of occurrences of an event over an interval of ten minutes. It can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. It is known that the mean number of occurrences in ten minutes is 5.3. 84. Refer to Exhibit 5-8. The probability that there are 8 occurrences in ten minutes is a. .0241 b. .0771 c. .1126 d. .9107

b. .0771

69. Four percent of the customers of a mortgage company default on their payments. A sample of five customers is selected. What is the probability that exactly two customers in the sample will default on their payments? a. 0.2592 b. 0.0142 c. 0.9588 d. 0.7408

b. 0.0142

If P(A) = 0.58, P(B) = 0.44, and P(A ∩ B) = 0.25, then P(A ∪ B) = a. 1.02 b. 0.77 c. 0.11 d. 0.39

b. 0.11

If P(A) = 0.4, P(B | A) = 0.35, P(A ∪ B) = 0.69, then P(B) = a. 0.14 b. 0.43 c. 0.75 d. 0.59

b. 0.43

The following represents the probability distribution for the daily demand of computers at a local store. Demand Probability 0 0.1 1 0.2 2 0.3 3 0.2 4 0.2 77. Refer to Exhibit 5-1. The expected daily demand is a. 1.0 b. 2.2 c. 2, since it has the highest probability d. of course 4, since it is the largest demand level

b. 2.2

Undergraduate Major Graduate School Business Engineering Others Total Yes 70 84 126 280 No 182 208 130 520 Total 252 292 256 800 25. Refer to Exhibit 2-2. Among the students who plan to go to graduate school, what percentage indicated "Other" majors? a. 15.75 b. 45 c. 54 d. 35

b. 45

The random variable x is the number of occurrences of an event over an interval of ten minutes. It can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. It is known that the mean number of occurrences in ten minutes is 5.3. 83. Refer to Exhibit 5-8. The expected value of the random variable x is approximately a. 2 b. 5 c. 10 d. 3

b. 5

The random variable x is the number of occurrences of an event over an interval of ten minutes. It can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. It is known that the mean number of occurrences in ten minutes is 5.3. 81. Refer to Exhibit 5-8. The random variable x satisfies which of the following Discrete Probability Distributions? a. normal b. Poisson c. binomial d. Not enough information is given to answer this question.

b. Poisson

Temperature is an example of a. a categorical variable b. a quantitative variable c. either a quantitative or categorical variable d. neither a quantitative nor categorical variable

b. a quantitative variable

42. Each individual outcome of an experiment is called a. the sample space b. a sample point c. an experiment d. an individual

b. a sample point

44. Any process that generates well-defined outcomes is a. an event b. an experiment c. a sample point d. a sample space

b. an experiment

48. Two events with nonzero probabilities a. can be both mutually exclusive and independent b. can not be both mutually exclusive and independent c. are always mutually exclusive d. are always independent

b. can not be both mustaully exclusive and independent

45. The counting rule that is used for counting the number of experimental outcomes when n objects are selected from a set of N objects where order of selection is not important is called a. permutation b. combination c. multiple step experiment d. None of these alternatives is correct.

b. combination

68. An experiment consists of determining the speed of automobiles on a highway by the use of radar equipment. The random variable in this experiment is a a. discrete random variable b. continuous random variable c. complex random variable d. simplex random variable

b. continuous random variable

A tabular summary of a set of data showing the fraction of the total number of items in several classes is a a. frequency distribution b. relative frequency distribution c. frequency d. cumulative frequency distribution

b. frequency

46. Two events are mutually exclusive a. if their intersection is 1 b. if they have no sample points in common c. if their intersection is 0.5 d. None of these alternatives is correct.

b. if the have no sample points in common

33. The first quartile a. contains at least one third of the data elements b. is the same as the 25th percentile c. is the same as the 50th percentile d. is the same as the 75th percentile

b. is the same as the 25th percentile

30. The 50th percentile is the a. mode b. median c. mean d. third quartile

b. median

35. The most frequently occurring value of a data set is called the a. range b. mode c. mean d. median

b. mode

9. Five hundred residents of a city are polled to obtain information on voting intentions in an upcoming city election. The five hundred residents in this study is an example of a(n) a. census b. sample c. observation d. population

b. sample

75. The key difference between the binomial and hypergeometric distribution is that with the hypergeometric distribution a. the probability of success must be less than 0.5 b. the probability of success changes from trial to trial c. the trials are independent of each other d. the random variable is continuous

b. the probability of success changes from trial to trial

In a scatter diagram, a line that provides an approximation of the relationship between the variables is known as a. approximation line b. trend line c. line of zero intercept d, line of zero slope

b. trend line

The random variable x is the number of occurrences of an event over an interval of ten minutes. It can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. It is known that the mean number of occurrences in ten minutes is 5.3. 85. Refer to Exhibit 5-8. The probability that there are less than 3 occurrences is a. .0659 b. .0948 c. .1016 d. .1239

c. .1016

56. If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P(A ∩ B) = a. 0.30 b. 0.15 c. 0.00 d. 0.20

c. 0.00

76. In a binomial experiment the probability of success is 0.06. What is the probability of two successes in seven trials? a. 0.0036 b. 0.0600 c. 0.0555 d. 0.2800

c. 0.0555

58. An experiment consists of four outcomes with P(E1) = 0.2, P(E2) = 0.3, and P(E3) = 0.4. The probability of outcome E4 is a. 0.500 b. 0.024 c. 0.100 d. 0.900

c. 0.100

53. If A and B are independent events with P(A) = 0.4 and P(B) = 0.6, then P(A ∩ B) = a. 0.76 b. 1.00 c. 0.24 d. 0.20

c. 0.24

57. If A and B are mutually exclusive events with P(A) = 0.4 and P(B) = 0.45, then P(A ∪ B) = a. 0.00 b. 0.15 c. 0.85 d. 0.2

c. 0.85

74. Assume that you have a binomial experiment with p = 0.5 and a sample size of 100. The value of the standard deviation is a. 50 b. 2 c. 25 d. 5

c. 25

28. The median of a sample will always equal the a. mode b. mean c. 50th percentile d. all of the above answers are correct

c. 50th percentile

A survey of 800 college seniors resulted in the following crosstabulation regarding their undergraduate major and whether or not they plan to go to graduate school. Undergraduate Major Graduate School Business Engineering Others Total Yes 70 84 126 280 No 182 208 130 520 Total 252 292 256 800 22. Refer to Exhibit 2-2. What percentage of the students does not plan to go to graduate school? a. 280 b. 52 c. 65 d. 32

c. 65

43. An experiment consists of selecting a student body president and vice president. All undergraduate student (freshmen through seniors) are eligible for these offices. How many sample points (possible outcomes as to the classifications) exist? a. 4 b. 16 c. 8 d. 32

c. 8

71. Which of the following statements about a discrete random variable and its probability distribution are true? a. Values of the random variable can never be negative. b. Some negative values of f(x) are allowed as long as ∑f(x) = 1. c. Values of f(x) must be greater than or equal to zero. d. The values of f(x) increase to a maximum point and then decrease.

c. Values of f(x) must be greater than or equal to zero.

Categorical data a. must be numeric b. must be nonnumeric c. cannot be numeric d. may be either numeric or nonnumeric

c. cannot be numerical

29. The median is a measure of a. relative dispersion b. absolute dispersion c. central location d. relative location

c. central location

All the data collected in a particular study are referred to as the a. inference b. variable c. data set d. None of these alternatives is correct.

c. data set

60. If P(A) = 0.50, P(B) = 0.60, and P(A ∩ B) = 0.30, then events A and B are a. mutually exclusive events b. not independent events c. independent events d. not enough information is given to answer this question

c. independent events

34. Which of the following is a measure of dispersion? a. percentiles b. quartiles c. interquartile range d. all of the above are measures of dispersion

c. interquartile range

72. The expected value of a discrete random variable a. is the most likely or highest probability value for the random variable b. will always be one of the values x can take on, although it may not be the highest probability value for the random variable c. is the average value for the random variable over many repeats of the experiment d. None of these alternatives is correct.

c. is the average value for the random variable over many repeats of the experiment

The percent frequency of a class is computed by a. multiplying the relative frequency by 10 b. dividing the relative frequency by 100 c. multiplying the relative frequency by 100 d. adding 100 to the relative frequency

c. multiplying the relative frequency by 100

38. When the data are skewed to the right, the measure of Skewness will be a. negative b. zero c. positive d. one

c. positive

32. The difference between the largest and the smallest data values is the a. variance b. interquartile range c. range d. coefficient of variation

c. range

26. A numerical value used as a summary measure for a sample, such as sample mean, is known as a a. population parameter b. sample parameter c. sample statistic d. population mean

c. sample statistic

20. When a histogram has a longer tail to the right, it is said to be a. symmetrical b. skewed to the left c. skewed to the right d. none of these alternatives is correct

c. skewed to the right

In a sample of 400 students in a university, 80, or 20%, are Business majors. Based on the above information, the school's paper reported that "20% of all the students at the university are Business majors." This report is an example of a. a sample b. a population c. statistical inference d. Data and Statistics

c. statistal inference

70. If you are conducting an experiment where the probability of a success is 0.2 per day and you are interested in finding the probability of 4 successes in in three days, the correct probability function to use is a. the standard normal probability density function b. the normal probability density function c. the Poisson probability function d. any probability as long as the tables are available

c. the poisson probability function

73. Which of the following is not a characteristic of an experiment where the binomial probability distribution is applicable? a. the experiment has a sequence of n identical trials b. exactly two outcomes are possible on each trial c. the trials are dependent d. the probabilities of the outcomes do not change from one trial to another

c. the trials are dependent

31. The 75th percentile is referred to as the a. first quartile b. second quartile c. third quartile d. fourth quartile

c. third quartile

1. A characteristic of interest for the elements is called a(n) a. sample b. data set c. variable d. None of these alternatives is correct.

c. variable

47. The range of probability is a. any value larger than zero b. any value between minus infinity to plus infinity c. zero to one d. any value between -1 to 1

c. zero to one

The following is a frequency distribution of the monthly expenditures for gasoline of 400 households in Chattanooga. Class Expenditure ($) # of households 1 0 and under 20 84 2 20 and under 40 128 3 40 and under 60 68 4 60 and under 80 56 5 80 and under 100 40 6 100 and over 24 What is the cumulative relative frequency of the 3rd class? a. .17 b. .53 c. .66 d. .70

d 0.70

52. If a coin is tossed three times, the likelihood of obtaining three heads in a row is a. zero b. 0.500 c. 0.875 d. 0.125

d. 0.125

64. A production process has been producing 10% defective items. A sample of three items is selected from the production process. What is the probability that all three items are defective? a. 0.30 b. 0.20 c. 30% d. 0.001

d. 0.20

If P(A) = 0.62, P(B) = 0.47, and P(A ∪ B) = 0.88, then P(A ∩ B) = a. 0.2914 b. 1.9700 c. 0.6700 d. 0.2100

d. 0.2100

Forty percent of all registered voters in a national election are female. A random sample of 5 voters is selected. 79. Refer to Exhibit 5-4. The probability that the sample contains 2 female voters is a. 0.0778 b. 0.7780 c. 0.5000 d. 0.3456

d. 0.3456

If P(A) = 0.68, P(A ∪ B) = 0.91, and P(A ∩ B) = 0.35, then P(B)= a. 0.22 b. 0.09 c. 0.65 d. 0.58

d. 0.58

Oriental Reproductions, Inc. is a company that produces handmade carpets with oriental designs. The production records show that the monthly production has ranged from 1 to 5 carpets. The production levels and their respective probabilities are shown below. Production Per Month x Probability f(x) 1 0.01 2 0.04 3 0.10 4 0.80 5 0.05 87. Refer to Exhibit 5-13. The standard deviation for the production is a. 4.32 b. 3.74 c. 0.374 d. 0.612

d. 0.612

54. If A and B are independent events with P(A) = 0.2 and P(B) = 0.6, then P(A ∪ B) = a. 0.62 b. 0.12 c. 0.60 d. 0.68

d. 0.68

Oriental Reproductions, Inc. is a company that produces handmade carpets with oriental designs. The production records show that the monthly production has ranged from 1 to 5 carpets. The production levels and their respective probabilities are shown below. Production Per Month x Probability f(x) 1 0.01 2 0.04 3 0.10 4 0.80 5 0.05 86. Refer to Exhibit 5-13. the expected monthly production level is a. 1.00 b. 4.00 c. 3.00 d. 3.84

d. 3.84

Undergraduate Major Graduate School Business Engineering Others Total Yes 70 84 126 280 No 182 208 130 520 Total 252 292 256 800 23. Refer to Exhibit 2-2. What percentage of the students' undergraduate major is engineering? a. 292 b. 29.2 c. 65 d. 36.5

d. 36.5

37. The standard deviation of a sample of 100 observations equals 64. The variance of the sample equals a. 8 b. 10 c. 6400 d. 4,096

d. 4096

51. An experiment consists of three steps. There are five possible results on the first step, six possible results on the second step, and two possible results on the third step. The total number of experimental outcomes is a. 9 b. 14 c. 36 d. 60

d. 60

Social security numbers consist of numeric values. Social security numbers are an example of a. a quantitative variable b. either a quantitative or a categorical variable c. an exchange variable d. a categorical variable

d. a categorical variable

A portion of the population selected to represent the population is called a. statistical inference b. Data and Statistics c. a census d. a sample

d. a sample

19. A graphical presentation of the relationship between two variables is a. an ogive b. a histogram c. either an ogive or a histogram, depending on the type of data d. a scatter diagram

d. a scatter diagram

16. Categorical data can be graphically represented by using a(n) a. histogram b. frequency polygon c. ogive d. bar chart

d. bar chart

A frequency distribution is a tabular summary of data showing the a. fraction of items in several classes b. percentage of items in several classes c. relative percentage of items in several classes d. number of items in several classes

d. number of items in several classes

66. The variance is a measure of dispersion or variability of a random variable. It is a weighted average of the a. square root of the deviations from the mean b. square root of the deviations from the median c. squared deviations from the median d. squared deviations from the mean

d. squared deviations from the median

36. The interquartile range is a. the 50th percentile b. another name for the variance c. the difference between the largest and smallest values d. the difference between the third quartile and the first quartile

d. the difference between the third quartile and the first quartile.