Ch. 2, Practice Problems: 11, 12, 13, 16, and 21
Ch. 3, Practice Problems: 14, 15, 22, and 25
11  For the following scores, find the (a) mean, (b) median, (c) sum of squared
deviations, (d) variance, and (e) standard deviation: 2, 2, 0, 5, 1, 4, 1, 3, 0, 0, 1, 4, 4, 0, 1,
4, 3, 4, 2, 1, 0
A.
2, 2, 0, 5, 1, 4, 1, 3, 0, 0, 1, 4, 4, 0, 1, 4, 3, 4, 2, 1, 0
Solution:
(a) Mean = sum/21 = 42/21 = 2
(b) Arrange the numbers in ascending order
0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 3, 3, 4, 4, 4, 4, 4, 5
Median = middle number = 2
(c) Sum of squared deviations:
x
xmean
(xmean)^2
2
0
0
2
0
0
0
2
4
5
3
9
1
1
1
4
2
4
1
1
1
3
1
1
0
2
4
0
2
4
1
1
1
4
2
4
4
2
4
0
2
4
1
1
1
4
2
4
3
1
1
4
2
4
2
0
0
1
1
1
0
2
4
sum
56
Sum of squared deviation = 56
(d) Variance = Sum of squared deviation/n – 1 = 56/(21 – 1) = 56/20 = 2.8
(e) Standard deviation = √variance = √2.8 = 1.673
12  For the following scores, find the (a) mean, (b) median, (c) sum of squared
deviations, (d) variance, and (e) standard deviation: 1,112; 1,245; 1,361; 1,372; 1,472
Solution:
(a) Mean = sum/21 = 6562/5 = 1312.4
(b) Arrange the numbers in ascending order
1112, 1,245, 1361, 1372, 1,472
Median = middle number = 1361
(c) Sum of squared deviations:
x
xmean
(xmean)^2
1112
200.4
40160.16
1245
67.4
4542.76
1361
48.6
2361.96
1372
59.6
3552.16
1472
159.6
25472.16
Sum
76089.2
Sum of squared deviations = 76089.2
(d) Variance = Sum of squared deviation/n – 1 = 76089.2/(5 – 1) = 76089.2/4 = 19022.3
(e) Standard deviation = √variance = √19022.3 = 137.9
13  For the following scores, find the (a) mean, (b) median, (c) sum of squared
deviations, (d) variance, and (e) standard deviation: 3.0, 3.4, 2.6, 3.3, 3.5, 3.2
Solution:
(a) Mean = sum/6 = 19/6 = 3.17
(b) Arrange the numbers in ascending order 2.6, 3.0, 3.2, 3.3, 3.4, 3.5
Median = (3.2 + 3.3)/2 = 6.5/2 = 3.25
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View Full Document(c) Sum of squared deviations:
x
xmean
(xmean)^2
3
0.17
0.0289
3.
4
0.23
0.0529
2.6
0.57
0.3249
3.
3
0.13
0.0169
3.5
0.33
0.1089
3.2
0.03
0.0009
sum
0.5334
Sum of squared deviations = 0.5334
(d) Variance = Sum of squared deviation/n – 1 = 0.5334/(6 – 1) = 0.5334/5 = 0.1067
(e) Standard deviation = √variance = √0.1067 = 0.3266
16 – A psychologist interested in political behavior measured the square footage of the
desks in the official office of four U.S governors and of four chief executive officers
(CEOs) of major U.S. corporations. The figures for the governors were 44, 36, 52, and 40
square feet. The figures for the CEOs were 32, 60, 48, 36 square feet.
(a) Figure the mean and standard deviation for the governors and for the CEOs.
(b) Explain what you have done to a person who has never had a course in statistics.
(c) Note that ways in which the means and standard deviations differ, and speculate on
the possible meaning of these differences, presuming that they are representative of U.S.
governors and large corporations’ CEOs in general.
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 Spring '11
 wright
 Standard Deviation, Cultural Anthropology, Null hypothesis, Statistical hypothesis testing

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