Stat-101, Midterm Exam (1)
Almajmaah Engineering College
King Saud University
Stat 101
25/4/1430
Name:
Group: 3
Academic Number:
Time allowed : 60 min.
Total =
Midterm Exam (1)
1. Indicate which of the following variables are quantitative and which are
qualitative.
a. Number of typographical errors in newspapers
b. Monthly TV cable bills
c. Spring break locations favored by college students
d. Number of cars owned by families
e. Lottery revenues of states
a., b., d. and e. are qualitative variables and c. is quantitative variable
a. and d. are quantitative variables and b., c. and e. are qualitative variables
All variables are qualitative
a., b., d. and e. are quantitative variables and c. is qualitative variable
All variables are quantitative
2. Explain whether each of the following constitutes a population or a sample.
a. Number of personal fouls committed by all NBA players during the 2005-2006 season
b. Yield of potatoes per acre for 40 pieces of land
c. Weekly salaries of all employees of a company
d. Cattle owned by 100 farmers in Iowa
e. Number of computers sold during the past week at all computer stores in Los Angeles
a., b., c., d. and e. constitute a population
a., c. and e. constitute a sample, b. and d. constitute a population
a., c. and e. constitute a population, b. and d. constitute a sample
a., b., c., d. and e. constitute a sample
a., b., c. and e. constitute a population, d. constitutes a sample
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Stat-101, Midterm Exam (1)
3. State which of the following is an example of sampling with replacement and
which is an example of sampling without replacement.
a. Selecting 20 patients out of 100 to test a new drug
b. selecting one professor to be a member of the university senate and then selecting
one professor from the same group to be a member of the curriculum committee
a. - sampling with replacement, b. - sampling with replacement
a. - sampling without replacement, b. - sampling without replacement
a. - sampling with replacement, b. - sampling without replacement
a. - sampling without replacement, b. - sampling with replacement
4.
In a heath survey, in U.S. adults were asked to rate their health. The table
below summarizes their responses.
Choose the correct pie chart for this percentage distribution .
State of health
Excellent
Very good
Good
Fair
Poor
a) Figure 3.
2
Percentage of Response
17.1
36.2
32.3
11.9
2.5
Figure 1.
Figure 2.
Figure 3.
Figure4.
b) Figure 1.
c) Figure 4
d) Figure 2
Stat-101, Midterm Exam (1)
5. A sample of 80 adults was taken and these adults were asked about the
number of credit cards they possess. The following table gives the frequency
distribution of their responses.
a. Find the class boundaries and class midpoints.
b. Do all classes have the same width? If so, what is this width?
(Choose the upper limit of the class previous to the first one to be -1.)
Number of Credit Cards
Number of Adults
0 to 3
17
4 to 7
28
8 to 11
22
12 to 15
9
16 to 19
4
6. Nixon Corporation manufactures computer monitors. The following data are
the numbers of computer monitors produced at the company for a sample of
30 days.
24
25
27
23
33
33
29
25
23
28
21
26
31
22
27
33
27
23
28
29
33
29
34
22
26
28
23
35
31
27
Construct a frequency distribution table using the classes 21-23, 24-26, 27-29, 30-32, and
33-35 to calculate the relative frequencies and percentages for all classes.
Round the values of relative frequencies to 3 decimal places and the values of percentage to
1 decimal place.
Number of Computer
Monitors Manufactured
21 to 23
24 to 26
27 to 29
30 to 32
33 to 35
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Stat-101, Midterm Exam (1)
7. The following table gives the frequency distribution of ages for all 50
employees of a company.
Age
Number of Employees
18 to 30
12
31 to 43
17
44 to 56
15
57 to 69
6
Select the correct drawing of an ogive for the cumulative percentage distribution.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 4.
Figure 2.
Figure 3.
Figure 1.
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Stat-101, Midterm Exam (1)
8. These data give the times (in minutes) taken to commute from home to work
for 20 workers.
10
50
64
33
47
5
11
23
39
26
26
31
17
8
15
19
29
41
21
22
Construct a stem-and-leaf display for these data. Arrange the leaves for each stem in
increasing order. Choose a correct display from the list.
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Stat-101, Midterm Exam (1)
9. The following data set belongs to a population:
6
-2
1
0 -12 15 12 9
Calculate the mean, median, and mode.
Round to two decimal places.
10.The Following are the temperatures (in degrees Fahrenheit) observed
during eight wintry days in London city (sample):
23
15
6
-7 -2 11 16 15
Compute the range, variance, and standard deviation.
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