Stat 101 – Sheet 4
King Saud University
Almajmaa’h Engineering College
STAT 101
1430/2009
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Sheet (4)
1. The following data set belongs to a population:
5
-7
2
0
-9
16
10
7
Calculate the range, variance and standard deviation.
2. The following data set belongs to a sample:
14
18
-10
8
8
-16
Calculate the range, variance and standard deviation.
3. The following data give the prices of seven textbooks randomly selected
from a University bookstore
$89 $57 $104 $73 $26 $121 $81
a) Find the mean for these data. Calculate the deviations of the data values
from the mean. Is the sum of these deviations zero?
b) Calculate the range, variance and standard deviation.
4. The following data give the numbers of car thefts that occurred in a city in
the past 12 days.
6 3 7 11
4
3
8
7
2
6
9
15
Calculate the range, variance and standard deviation.
5. The following data give the temperature (in Fahrenheit) observed during
eight wintry days in a Midwestern city.
23
14
6
-7
-2
11
16
19
Compute the range, variance and standard deviation.
Dr. SaMeH
Page 1
Stat 101 – Sheet 4
6. Using the population formulas, find the mean, variance and standard
deviation for the following grouped data.
x
2-4
5-7
8-10
11-13
14-16
f
5
9
14
7
5
7. Using the sample formulas, find the mean, variance and standard deviation
for the grouped data displayed in the following table.
x
0 to less than 4
4 to less than 8
8 to less than 12
12 to less than 16
16 to less than 20
20 to less than 24
f
17
23
15
11
8
6
8. The following table gives information on the amounts (in dollars) of
electrical bills for August 2002 for a sample of 50 families.
Amount of electrical Bill
(dollars)
0 to less than 20
20 to less than 40
40 to less than 60
60 to less than 80
80 to less than 100
Number of
families
5
16
11
10
8
Find the mean, variance and standard deviation.
9. For 50 airplanes that arrived late at an airport during a week, the time by
which they were late was observed. In the following table, x denotes the
time (in minutes) by which an airplane was late and f denotes the number
of airplanes.
x
0 to less than 20
20 to less than 40
40 to less than 60
60 to less than 80
80 to less than 100
f
14
18
9
5
4
Find the mean, variance and standard deviation.
Dr. SaMeH
Page 2