e.
For which variables are arithmetic operations appropriate and for which are they not appropriate?
ANS:
a.
7
b.
3
c.
7
d.
Hi: quantitative, Lo: quantitative, Condition: categorical
e.
Hi: appropriate, Lo: appropriate, Condition: not appropriate
PTS: 1 TOP: Descriptive Statistics
4. The following data shows the yearly income distribution of a sample of 200 employees at MNM, Inc.
Yearly Income
(In $1,000s)
Number
of Employees
20 - 24
2
25 - 29
48
30 - 34
60
35 - 39
80
40 - 44
10
a.
What percentage of employees has yearly incomes of $35,000 or more?
b.
Is the figure (percentage) that you computed in Part a an example of statistical inference? If no, what kind of statistics does it represent?
c.
Based on this sample, the president of the company said that "45% of all our employees' yearly incomes are $35,000 or more." The president's statement represents what kind of statistics?
d.
With the statement made in Part c, can we be assured that more than 45% of all employees' yearly incomes are at least $35,000? Explain.
e.
What percentage of employees of the sample has yearly incomes of $29,000 or less?
f.
How many variables are presented in the above data set?
g.
The above data set represents the results of how many observations?
ANS:
a.
45%
b.
No, it is descriptive statistics.
c.
statistical inference
d.
No, this is simply an inference and approximation based on the sample information.
e.
25%
f.
2
g.
200
PTS: 1 TOP: Descriptive Statistics
5. A recent issue of a national magazine reported that in a national public opinion survey conducted among 2,000 individuals, 56% were in favor of gun control, 40% opposed gun control, and 4% had no opinion on the subject.
a.
What is the sample in this survey?
b.
Based on the sample, what percentage of the population would you think is in favor of gun control?
c.
Based on the sample, what percentage of the population would you think have no opinion on the subject?
ANS:
a.
The 2000 individuals who were approached
b.
56%
c.
4%
PTS: 1 TOP: Descriptive Statistics
6. The following table shows the starting salaries of a sample of recent business graduates.
Income (In $1,000s)
Number of Graduates
15 - 19
40
20 - 24
60
25 - 29
80
30 - 34
18
35 - 39
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?
ANS:
a.
10%
b.
50%
c.
80%
PTS: 1 TOP: Descriptive Statistics
7. Michael, Inc., a manufacturer of electric guitars, is a small firm with 50 employees. The table below shows the hourly wage distribution of the employees.
Hourly Wages (In Dollars)
Number of Employees
10 - 13
8
14 - 17
12
18 - 21
20
22 - 25
10
a.
How many employees receive hourly wages of at least $18?
b.
What percentage of the employees has hourly wages of at least $18?
c.
What percentage of the employees has hourly wages of less than $14?