Download Practice Test 1

Bus Stat Practice Test 1
**Note this is Longer Than a normal test to give more Practice
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
____
____
____
____
____
____
____
1. The scale of measurement that is simply a label for the purpose of identifying the attribute of an element is the
a. ratio scale
b. nominal scale
c. ordinal scale
d. interval scale
2. The nominal scale of measurement has the properties of the
a. ordinal scale
b. only interval scale
c. ratio scale
d. None of these alternatives is correct.
3. The scale of measurement that is used to rank order the observation for a variable is called the
a. ratio scale
b. ordinal scale
c. nominal scale
d. interval scale
4. The scale of measurement that has an inherent zero value defined is the
a. ratio scale
b. nominal scale
c. ordinal scale
d. interval scale
5. Arithmetic operations are appropriate for
a. only the ratio scale
b. only the interval scale
c. the nominal scale
d. None of these alternatives is correct.
6. Data
a. are always be numeric
b. are always nonnumeric
c. are the raw material of statistics
d. None of these alternatives is correct.
7. Another name for "observations" is
a. views
b. variables
c. cases
d. None of these alternatives is correct.
8. Ordinary arithmetic operations are meaningful
a. only with qualitative data
b. only with quantitative data
c. either with quantitative or qualitative data
d. None of these alternatives is correct.
1
____
____
____
____
____
____
9. Social security numbers consist of numeric values. Therefore, social security is an example of
a. a quantitative variable
b. either a quantitative or a qualitative variable
c. an exchange variable
d. a qualitative variable
10. Statistical studies in which researchers control variables of interest are
a. experimental studies
b. control observational studies
c. non-experimental studies
d. observational studies
11. A portion of the population selected to represent the population is called
a. statistical inference
b. descriptive statistics
c. a census
d. a sample
12. 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
13. The owner of a factory regularly requests a graphical summary of all employees' salaries. The graphical
summary of salaries is an example of
a. a sample
b. descriptive statistics
c. statistical inference
d. an experiment
14. The Department of Transportation of a city has noted that on the average there are 17 accidents per day. The
average number of accidents is an example of
a. descriptive statistics
b. statistical inference
c. a sample
d. a population
Exhibit 1-2
In a sample of 1,600 registered voters, 912, or 57%, approve of the way the President is doing his job.
____ 15. Refer to Exhibit 1-2. The 57% approval is an example of
a. a sample
b. descriptive statistics
c. statistical inference
d. a population
2
____ 16. Since a sample is a subset of the population, the sample mean
a. is always smaller than the mean of the population
b. is always larger than the mean of the population
c. must be equal to the mean of the population
d. can be larger, smaller, or equal to the mean of the population
____ 17. 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
____ 18. The sum of the relative frequencies for all classes will always equal
a. the sample size
b. the number of classes
c. one
d. any value larger than one
Exhibit 2-1
The numbers of hours worked (per week) by 400 statistics students are shown below.
Number of hours
0- 9
10 - 19
20 - 29
30 - 39
Frequency
20
80
200
100
____ 19. Refer to Exhibit 2-1. The number of students working 19 hours or less
a. is 80
b. is 100
c. is 180
d. is 300
____ 20. Refer to Exhibit 2-1. The relative frequency of students working 9 hours or less
a. is 20
b. is 100
c. is 0.95
d. 0.05
____ 21. Refer to Exhibit 2-1. The cumulative relative frequency for the class of 20 - 29
a. is 300
b. is 0.25
c. is 0.75
d. is 0.5
____ 22. Refer to Exhibit 2-1. The percentage of students who work at least 10 hours per week is
a. 50%
b. 5%
c. 95%
d. 100%
3
____ 23. Data that provide labels or names for categories of like items are known as
a. qualitative data
b. quantitative data
c. label data
d. category data
____ 24. A tabular method that can be used to summarize the data on two variables simultaneously is called
a. simultaneous equations
b. crosstabulation
c. a histogram
d. an ogive
____ 25.  is an example of a
a. population parameter
b. sample statistic
c. population variance
d. mode
____ 26. The hourly wages of a sample of 130 system analysts are given below.
mean = 60
mode = 73
median = 74
range = 20
variance = 324
The coefficient of variation equals
a. 0.30%
b. 30%
c. 5.4%
d. 54%
Exhibit 3-1
The following data show the number of hours worked by 200 statistics students.
Number of Hours
0
10
20
30
- 9
- 19
- 29
- 39
Frequency
40
50
70
40
____ 27. Refer to Exhibit 3-1. The class width for this distribution
a. is 9
b. is 10
c. is 11
d. varies from class to class
____ 28. 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
4
____ 29. The most frequently occurring value of a data set is called the
a. range
b. mode
c. mean
d. median
Exhibit 3-3
A researcher has collected the following sample data. The mean of the sample is 5.
3
5
12
3
2
____ 30. Refer to Exhibit 3-3. The coefficient of variation is
a. 72.66%
b. 81.24%
c. 264%
d. 330%
____ 31. Which of the following symbols represents the mean of the population?
a. 2
b. 
c. 
d.
____ 32. Which of the following symbols represents the size of the sample
a. 2
b. 
c. N
d. n
____ 33. The symbol 2 is used to represent
a. the variance of the population
b. the standard deviation of the sample
c. the standard deviation of the population
d. the variance of the sample
____ 34. Of five letters (A, B, C, D, and E), two letters are to be selected at random. How many possible selections are
there?
a. 20
b. 7
c. 5!
d. 10
____ 35. If two events are independent, then
a. they must be mutually exclusive
b. the sum of their probabilities must be equal to one
c. their intersection must be zero
d. None of these alternatives is correct..
____ 36. The intersection of two mutually exclusive events
a. can be any value between 0 to 1
b. must always be equal to 1
c. must always be equal to 0
d. can be any positive value
5
____ 37. Which of the following statements is(are) always true?
a. -1  P(Ei) 1
b. P(A) = 1 - P(Ac)
c. P(A) + P(B) = 1
d. P  1
____ 38. The multiplication law is potentially helpful when we are interested in computing the probability of
a. mutually exclusive events
b. the intersection of two events
c. the union of two events
d. conditional events
____ 39. A method of assigning probabilities which assumes that the experimental outcomes are equally likely is
referred to as the
a. objective method
b. classical method
c. subjective method
d. experimental method
____ 40. The probability assigned to each experimental outcome must be
a. any value larger than zero
b. smaller than zero
c. at least one
d. between zero and one
6
Short Answer: For credit make sure to show all work and formulas used if necessary.
1.The following table shows the starting salaries of a sample of recent business graduates.
Income (In $1,000s)
15 - 19
20 - 24
25 - 29
30 - 34
35 - 39
Number of Graduates
40
60
80
18
2
a. What percentage of graduates in the sample had starting salaries of at least $30,000?
b. Of the graduates in the sample, what percentage had starting salaries of less than $25,000?
c. Based on this sample, what percentage of all business graduates do you estimate to have
starting salaries of at least $20,000?
2.Forty shoppers were asked if they preferred the weight of a can of soup to be 6 ounces, 8 ounces, or 10
ounces. Below you are given their responses.
6
10
8
6
6
10
8
8
6
8
8
8
10
8
10
8
8
6
8
10
8
6
8
10
8
6
6
8
10
8
10
10
6
6
8
8
6
6
6
6
a. Construct a frequency distribution and graphically represent the frequency distribution.
b. Construct a relative frequency distribution and graphically represent the relative frequency
distribution.
3.The frequency distribution below was constructed from data collected from a group of 25 students.
Height in Inches
58 - 63
64 - 69
70 - 75
76 - 81
82 - 87
88 - 93
94 - 99
Frequency
3
5
2
6
4
3
2
a. Construct a relative frequency distribution.
b. Construct a cumulative frequency distribution.
c. Construct a cumulative relative frequency distribution.
7
4.The probability of an economic decline in the year 2000 is 0.23. There is a probability of 0.64 that we will
elect a republican president in the year 2000. If we elect a republican president, there is a 0.35 probability of an
economic decline. Let "D" represent the event of an economic decline, and "R" represent the event of election
of a Republican president.
a. Are "R" and "D" independent events?
b. What is the probability of a Republican president and economic decline in the year 2000?
c. If we experience an economic decline in the year 2000, what is the probability that there
will a Republican president?
d. What is the probability of economic decline or a Republican president in the year 2000?
Hint: You want to find P(D  R).
5. A sample of 9 mothers was taken. The mothers were asked the age of their oldest child. You are given their
responses below.
3
a.
b.
c.
d.
e.
f.
g.
h.
12
4
7
14
6
2
Compute the mean.
Compute the variance.
Compute the standard deviation.
Compute the coefficient of variation.
Determine the 25th percentile.
Determine the median
Determine the 75th percentile.
Determine the range.
9
11
6. The following observations are given for two variables.
y
x
5
2
8
12
18
3
20
6
22
11
30
19
10
18
7
9
a.
Compute and interpret the sample covariance for the above data.
b.
Compute and interpret the sample correlation coefficient.
8
7. You are given the following information on Events A, B, C, and D.
P(A  D) = .6
P(AB) = .3
P(A  C) = .04
P(A  D) = .03
Compute P(D).
Compute P(A  B).
Compute P(AC).
Compute the probability of the complement of C.
Are A and B mutually exclusive? Explain your answer.
Are A and B independent? Explain your answer.
Are A and C mutually exclusive? Explain your answer.
Are A and C independent? Explain your answer.
P(A) = .4
P(B) = .2
P(C) = .1
a.
b.
c.
d.
e.
f.
g.
h.
9