1. 1.Statistical inference
a. refers to the process of drawing inferences about the sample based on the characteristics of
the population
b. is the same as descriptive statistics
c. is the process of drawing inferences about the population based on the information taken
from the sample
d. is the same as a census
ANS: C
2.The collection of all elements of interest in a particular study is
a. the population
b. the sampling
c. statistical inference
d. descriptive statistics
ANS: A
3.The height of a building, measured in feet, is an example of
a. qualitative data
b. either qualitative or quantitative data
c. feet data
d. quantitative data
ANS: D
4.An interviewer has made an error in recording the data. This type of error is known as
a. an experimental error
b. a data acquisition error
c. a non-experimental error
d. a conglomerate error
ANS: B
4. Qualitative data can be graphically represented by using a(n)
a. histogram
b. frequency polygon
c. ogive
d. bar graph
ANS: D
5. 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
ANS: D

2. 5. 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
ANS: D
6. A histogram is said to be skewed to the left if it has a
a. longer tail to the right
b. shorter tail to the right
c. shorter tail to the left
d. longer tail to the left
ANS: D
7. 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
ANS: B
8.When computing the mean of a set of values xi, the value of ∑xi
a. can never be zero
b. can never be negative
c. must always be positive
d. can be any value
ANS: D
9. In computing the mean of a sample, the value of ∑xi is divided by
a. n
b. n - 1
c. n + 1
d. n - 2
ANS: A
10. 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

3. d. the data set is from a census
ANS: A
11. 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.
ANS: A
12. The mean of the sample
a. is always smaller than the mean of the population from which the sample was taken
b. can never be zero
c. can never be negative
d. None of these alternatives is correct.
ANS: D
13. The variance of the sample
a. can never be negative
b. can be negative
c. cannot be zero
d. cannot be less than one
ANS: A
14. 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
ANS: A
15. 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
16. A graphical device used for enumerating sample points in a multiple-step experiment is a
a. bar chart
b. pie chart
c. histogram
d. None of these alternatives is correct.