1. A politician who is running for the office of governor of a state with 3 million registered voter commissions a survey. In the
survey, 53.6% of the 5,000 registered voters interviewed say they plan to vote for him. The population of interest is the: a. 3
million registered voters in the state
2. A summary measure that is computed from a sample to descrbe a characteristic of the population is called b. a statistic
3. A summary measure that is computed from a population is called a. a parameter
4. Descriptive statistics deals with methods of: d. All of the above: organizing data AND summarizing data AND presenting
data In a convenient and informative way
5. When data are collected in a statistical study for only a portion or subset of all elements of interest, we are using: a. a
sample
6. You asked five of your classmates about their height. On the basis of this information, you stated that the average height of
all students in your university or college is 67 inches. This is an example of: b. statistical inference
7. Which of the following is not the goal of descriptive statistics? d. Estimating characteristics of the population
8. Which of the following statements is not true? c. In the language of statistics, population refers to a group of people
9. the most appropriate type of chart for determining the number of observations at or below a specific value is: d. a
cumulative frequency ogive
10. The best type of chart for comparing two sets of categorical data is: d. a bar chart
11. The total area of the six bars in a relative frequency histogram for which the width of each bar is five units is: b. 5
12. which of the following statements about pie charts is false? b. Pie charts are usually used to display the relative sizes of
categories for interval data.
13. The total area of the bars in a relative frequency histogram: c. depends on the width of each bar
14. Which of the following statements is false? b. All calculations are permitted on nominal data
15. Which of the following statements is false? b. The intervals in a frequency distribution may overlap to ensure that each
observation is assigned to an interval
16. In general, incomes of employees in large firms tend to be a. positively skewed
17. The relative frequency of a class is computed by c. dividing the frequency of the class by the total number of
observations in the data set
18. A modal class is the class that includes a. the largest number of observations
19. The sum of the relative frequencies for all classes will always equal d. one
20. The two graphical techniques we usually use to present nominal data are c. bar chart and pie chart
21. The most important and commonly graphical presentation of interval data is a b. histogram
22. The relationship between two interval variables is graphically displayed by a a. scatter diagram
23. The effect of making the slope of a line graph appear steeper can be created by: d. Both a and b: stretching the vertical
axis AND horizontal axis shrinking the
24. Possible methods of creating distorted impressions with bar charts include: d. All of the above: Stretching the vertical
axis AND shrinking the horizontal axis AND Constructing the bars so that their widths are proportional to their heights
25. You are less likely to be misled by a graph it you: c. Both a and b: Focus your attention on the numerical values that the
graph represents AND Avoid being influenced by the graph's caption
26. Possible methods of graphical deception include: e. All of the above: A graph without a scale on one axis & A graph's
caption that influences the impression of the viewer & Only absolute changes in value, rather than percentage changes,
are reported & Stretching the vertical axis or shrinking the horizontal axis.
27. which of the following is not a characteristic of graphical excellence? a. The graph presents small data sets concisely and
coherently while large data sets are easily presented in tabular form.
28. which of the following statements about the arithmetic mean is not always correct? b. Half of the observations are on
either side of the mean
29. In a histogram, the proportion of the total area which must be to the left of the median is: a. exactly 0.50
30. whIch of the following statements is true? a. The sum of the deviations from the arithmetic mean is always zero
31. If two data sets have the same range: a. the distances from the smallest to largest observations in both sets will be the
same
32. which of the following statements is true? c. when the distribution is 9ymmetric and unimodal, mean = median = mode
33. In a histogram, the proportion of the total area which must be to the right of the mean is d. exactly 0.50 if the
distribution is symmetric and unimodal
34. A sample of 20 observations has a standard deviation of 3. The sum of the squared deviations from the sample mean is: e.
171
35. which measure of central location is meaningful when the data are nominal? d. The mode
36. whIch of the following are measures of the linear relationship between two variables? d. Both a and b :The covadance &
The coefficient of correlation
37. A perfect straight line sloping downward would produce a correlation coeffiaent equal to b. -1
38. Generally speaking, if two variables are unrelated (as one increases, the other shows no pattern), the covariance will be c.
a positive or negative number close to zero
39. which measure of central location is appropriate whenever we wish to find the average growth rate, or rate of change, in
a variable overtime? b. The geometric mean
40. which measure of central location is appropriate whenever we wish to estimate the expected mean return, or growth
rate, for a single year in the future? a. The arithmetic mean
41. chebyshev’s Theorem states that the percentage of measurements in a data set that fall within three standard deviations
of their mean is: d. atleast89%
42. The Empirical Rule states that the approximate percentage of measurements in a data set (providing that the data set has
a bell-shaped distribution) that fall within two standard deviations of their mean is approximately: c. 95%
43. Since the population is always larger than the sample, the population mean: e. can be smaller than, or larger than, or
equal to the sample mean
44. Which of the following summary measures is affected most by outliers? c. The range
45. The average score for a class of 30 students was 75. The 20 male students In the class averaged 70. The 10 female
students in the class averaged: b. 85
46. Which of the following is not a measure of variability? d. The standard deviation
47. Expressed in percentiles, the interquartile range is the difference between the c. 25% and 75% values
48. Which of the following statements is true for the following data values: 7,5, 6,4,7,8, and 12? a. The mean, median and
mode are all equal
49. The difference between a sample mean and the population mean is called: c. sampling error.
50. Which of the following sampling plans does use random methods of selections? d. All of the above: Simple random
sampling & Stratified random sampling & Cluster sampling.
51. A pharmaceutical company interested in measuring how often physicians prescribe a certain drug has selected a simple
random sample from each of two groups: M.D. and D.O. what Is this type of sampling called? c. Stratified random sampling.
52. which of the following does not characterize stratified random sampling? d. Nonrandom sampling is used.
53. when every possible sample with the same number of observations is equally likely to be chosen, the selected sample is
called: a. simple random sample.
54. which of the following is not an example of primary data? d. Financial data tapes that contain data compiled from the
New York stock Exchange.
55. which of the following must be avoided in designing a questionnaire? b. Leading questions.
56. when the population Is divided into mutually exclusive sets, and then a simple random sample is drawn from each set,
this is called: b. stratified random sampling.
57. which of the following is an example of nonsampling errors? d. All of the above: Errors that arise from the recording of
incorrect responses & when responses are not obtained from some members of the sample & when some members of the
target population cannot possibly be selected in the sample
58. which of the following statements is correct in questionnaire design? d. All of the above are correct statements: The
questionnaire should be kept as short as possible, and the questions themselves should also be kept short & A mixture of
dichotomous, multiple-choice, and open-ended questions may be used & Leading questions must be avoided
59. An approach of assigning probabilities which assumes that all outcomes of the experiment are equally likely is referred to
as the: C. classical approach
60. if P(A) = 0.84, P(B) =0.76 and P(A or B) =0.90, then P(A ancd B) is: c. 0.70
61. if P(A) = 0.35, P(B) = 0.45 and P(A and B) =0.25, then P(A/B) is: d. 0.556
62. if P(A): 0.20, P(B) = 0.30 and PA and 8) = 0.06, then A and B are: b. independent events
63. If A and B are mutually exclusive events with P(A) = 0.70, then P(B): c. cannot be larger than 0.30
64. If A and B are independent events with P(A) = 0.60 and P(A/B) = 0.60, then PB) is: d. Cannot be determined with the
information given
65. If P(A) = 0.65, P(B) = 0.58, and P(A and B) = 0.76, then P(A or B) is: b. 0.47
66. If you roll an unbiased die 50 times, you should expect an even number to appear: d. on the average, 25 out of the 50
rolls
67. The collection of all possible outcomes of an experiment is called: b. a sample space
68. which of the following is not an approach to assigning probabilities? b. Trial and error approach
69. A useful graphical method of constructing the sample space for an experiment is: a. a tree diagram
70. A sample space of an experiment consists of the following outcomes: 1, 2, 3, 4, 5. which of the following is a simple
event? c. 3
71. Suppose P(A) = 0.35. The probability of complement of A is: c. 0.65
72. Assume that you invested $10,000 in each of three stocks. Each stock can increase in value, decrease in value, or remain
the same. Drawing a probability tree for this experiment will show that the number of possible outcomes is: d. 27
73. An experiment consists of tossing 3 unbiased coins simultaneously. Drawing a probability tree for this experiment will
show that the number of simple events in this experiment is: d. None of the above answers is correct.
74. If the events A and B are independent with P(A) =0.30 and P(B) =0.40, then the probability that both events will occur
simultaneously is: b. 0.12
75. Two events A and B are said to be independent if a. P(A and B)= P(A).P(B)
76. Two events A and B are said to mutually exclusive if d. P(A and B)=0
77. which of the following statements is always correct? d. P(A) = 1-P(A^c)
78. which of the following is a requirement of the probabilities assigned to the outcomes 0i? c. 0 ≤ P (Oi) ≤1 for each i
79. An experiment consists of three stages. There are two possible outcomes in the first stage, three possible outcomes in the
second stage, and four possible outcomes in the third stage. Drawing a tree diagram for this experiment will show that the
total number of outcomes is: b. 24
80. which of the following statements is correct given that the events A and B have nonzero probabilities? a. A and B cannot
be both independent and mutually exclusive
81. If A and B are mutually exclusive events, with P(A) = 0.20 and P(B) = 0.30, then P(A and B) is: c. 0.00
82. If A and B are independent events with P(A) = 0.60 and P(B) = 0.70, then the probability that A occurs or B occurs or both
occur is: b. 0.88
83. If A and B are mutually exclusive events with P(A)= 0.30 and P(B) =0.40, then P(A or B) Is: c. 0.70
84. If A and B are independent events with P(A) = 0.20 and P(B) =0.60, then P(A/B) is: a. 0.20
85. If P(A) = 0.25 and P(B) = 0.65, then P(A and B) is: d. Cannot be determined from the information given
86. If a coin is tossed three times and a statistician predicts that the probability of obtaining three heads in a row is 0.125,
which of the following assumptions is irrelevant to his prediction? a. The events are dependent
87. If an experiment consists of five outcomes with P(01) =0.10, P(O2) =0.20, P(03) =0.30, P(04) =040, then P(05) is d. 0.00
88. Of the last 500 customers entering a supermarket, 50 have purchased a wireless phone. If the classical approach for
assigning probabilities is used, the probability that the next customer will purchase a wireless phone is c. 0.50
89. Of the last 500 customers entering a supermarket, 50 have purchased a wireless phone. If the relative frequency
approach tor assigning probabilities is used, the probability that the next customer will purchase a wireless phone is a. 0.10
90. if A and B are mutually exclusive events, with P(A) = 0.20 and P(B) = 0.30, then P(A/B) is: C. 0.00
91. A study has been done to determine whether or not a certain drug leads to an improvement in symptoms for patients
with a particular medical condition. The results are shown in the following table. Drug: (I270, NI530, Total 800) No Drug:
(I120, NI280, Total 400) Total: (I390, NI810, Total 1200) what is the probability that a patient shows improvement if it is
known that the patient was given the drug? d. 0.3375
92. Suppose it is known that the patient shows Improvement. Based on this table, what is the (empirical) probability that the
patient was given the drug? c. 0.4875
93. A box contains four red, two white, and three green marbles, all of which are the same size. Two marbles are selected one
after the other from the box, without replacement. What is the probability that the marbles are the same color? c. 0.278
94, A company has 3 plants at which it produces a certain Item. 30% are produced at Plant A, 50% at Plant B, & 20% at Plant
C. suppose that 1%, 4% & 3% of the items produced at Plants A, B & C respectively are defective. If an item is selected at
random from all those produced, what is the probability that the item was produced at Plant B & is defective b. 0.02
95. A company has three plants at which it produces a certain item. 30% are produced at Plant A, 50% at Plant B, and 20% at
Plant c. Suppose that 1%, 4% and 3% of the items produced at Plants A, B and C respectively are defective. If an item is
selected at random from all those produced, what Is the probability that it Is defective a. 0.029
96. The weighted average of the possible values that a random variable x can assume, where the weights are the probabilities
of occurrence of those values: c. expected value
97. The number of accidents that occur annually on a busy stretch of highway is an example of a. a discrete random variable
98. A function or rule that assigns a numerical value to each simple event of an experiment is called: d. a random variable
99, if X and Y are any random variables, which of the following identities is not always true? b. V(X+Y) = V(X) +VY
100. If x and y are random variables, the sum of all the conditional probabilities of X given a specific value of Y will always be:
b. 1.0
101. A statistical measure of the strength of the linear relationship between two random variables x and y is referred to as
the: c. covariance
102. A table, formula, or graph that shows all possible values a random variable can assume, together with their associated
probabilities is called a: a. discrete probability distribution
103. If X and Y are random variables with E(X) = 5 and E(Y) = 8, then E(2x+3y) is: a. 34
104. which of the following is not a characteristic of a binomial experiment? b. Each trial results In two or more outcomes.
105. The expected value, E(X), of a binomial probability distribution with n trials and probability p of success is: C. np
106. The expected number of heads in 100 tosses of an unbiased coin is c.50
107. The variance of a binomial distribution for which n= 100 and p = 0.20 is: d. 16
108. which of the following is (are) required condition(s) for the distribution of a discrete random variable x that can assume
values xi? c. Both a and b are required conditions: 0≤p(xi)≤1 for all xi & ∑xi p(xi)=1
109. which of the following is not a required condition for the distribution of a discrete random variable x that can assume
values xi? c. p(xi)>1 for all xi
110. The binomial probability distribution is used with a. a discrete random variable
111. Twenty five percent of the students in an English class of 100 are international students. The standard deviation of this
binomial distribution is d. 4.33
112. In the notation below, x is the random variable, c is a constant, and V refers to the variance. which of the following laws
of variance is not correct? c. v(X+c)=v(X)+c
113. Given that Z is a standard normal random variable, P(-1.0≤ Z≤ 1.5) is a. 0.7745
114. Given that Z is a standard normal variable, the value z for which P(Z ≤ z) = 0.2580 is c. -0.65
115. If x is a normal random variable with a standard deviation of 10, then 3x has a standard deviation equal to c.30
116. Given that X is a normal variable, which of the following statements is (are) true? d. All of the above statements are
true: The variable x + 5 is also normally distributed & The variable X -5 is also normally distributed & The variable 5x is also
normally distributed
117. A standard normal distribution is a normal distribution with a. a mean of zero and a standard deviation of one
118. If Z is a standard normal random variable, then P(-1.75 ≤Z ≤-1.25) is d. 0.0655
119. If z Is a standard normal random variable, then the value z for which P(-z≤ Z ≤z) equals 0.8764 is b. 1.54
120. If the continuous random variable X is uniformly distributed over the interval (15,25), then the mean of x is c. 20
121. if the random variable X is normally distributed with a mean of 75 and a standard deviation of 8, then P(x ≥ 75) is b.
0.500
122. Given that Z is a standard normal random variable, what is the value of z if the area to the right of z is 0.1949? c. 0.86
123. Given that Z is a standard normal random variable, what is the value of Z if the area to the right of Z is 0.9066? b. -1.32
124. Given that Z is a standard normal random variable, P(z> -1.58)is c. 0.9429
125. Given that the random variable X is normally distributed with a mean of 80 and a standard deviation of 10, P(85≤X ≤90)is
d. 0.1498
126. Which of the following is always true for all probability density functions of continuous random variables? c. The area
under the curve is 1.0
127. What proportion of the data from a normal distribution is within three standard deviations from the mean? d. 0.9544
128. Given that Z is a standard normal random variable, the area to the left of a value z is expressed as b. P(Z≤z)
129. Which of the following distributions are symmetrical? b. Uniform and normal
130. If the z-value for a given value x of the random variable x is z = 1.96, and the distribution of x is normally distributed with
a mean of 60 and a standard deviation of 6, to what x value does this z-value correspond? a. 71.76
131. If Z is a standard normal random variable, the area between z =0.0 and z =1.30 is 0.4032, while the area between z= 0.0
and z = 1.50 is 0.4332. What is the area between z = -1.30 and z = 1.50? d. 0.8364
132. If z is a standard normal random variable, the area between z = 0.0 and z =1.50 compared to the area between z= 1.5
and z=3.0 will be b. larger
133. The probability that a continuous random variable X will assume any specific value is a. 0.0
134. The expected value, E(X), of a uniform random variable x defined over the interval a ≤x≤ b, is c. (a+b)/2
135. The probability density function, f(x), for any continuous random variable X, represents d. the height of the function at x
136. The height of the function for a uniform probability density function f(x) b. is the same for various values of the random
variable X
137. Which of the following is not true for a random variable x that is uniformly distributed over the interval a≤x≤b c. o⌐=(b—
a)/6
138. The function f(x) that defines the probability distribution of a continuous random variable x is a d. probability density
function
139. The probability density function f(x) for a uniform random variable x defined over the interval [2,10] is a. 0.125
140. If the random variable X is uniformly distributed between 40 and 50, then P(35 ≤ X ≤45) is b. 0.5
141. Which of the following is not true for a normal distribution? c. It is discrete
142. Which of the following distributions is considered the cornerstone distribution of statistical inference? b. Normal
distribution
143. The probability density function f(x) of a random variable X that is normally distributed is completely determined once
the d. mean and variance of x are specified
144. The probability density function f(x) of a random variable x that is uniformly distributed between a and b is a. 1/(b—a)
145. Which of the following is not a characteristic for a normal distribution? b. The mean is always zero
146. Given that z is a standard normal variable, the variance of z c. is always equal to 1.0
147. Given that Z is a standard normal random variable, a negative value z indicates that a. the value z is to the left of the
mean
148. Given that z is a standard normal random variable, the mean of z is c. always equal to zero
149. A larger standard deviation of a normal distribution indicates that the distribution becomes b. flatter and wider
150. Given that Z is a standard normal variable, the value z for which P(Z ≤z) = 0.6736 is b. 0.45
151. Which of the following statements is false? b. The chi-squared distribution is symmetrical
152. Which of the following statements is correct regarding the percentile points of the r distribution? d. F0.90,10,20 =
1/F0.10,20,10