Practice Problems Chapter Two
2
Practice Problems
11. for the following scores: 2, 2, 0, 5, 1, 4, 1, 3, 0, 0, 1, 4, 4, 0, 1, 4, 3, 4, 2, 1, 0
Find the:
(a)
Mean = 2
(b) Median
= 2
(c) Sum of squared deviations
= 56
(d) Variance
= 2.8
(e) Standard deviation
= 1.673
12. for the following scores: 1,112; 1,245; 1,361; 1,372; 1,472
Find the:
(a) Mean
= 1,312.4
(b) Median
= 1,361
(c) Sum of squared deviations
= 76,089.2
(d) Variance
= 19,022.3
(e) Standard deviation
= 137.921
13. for the following scores: 3.0, 3.4, 2.6, 3.3, 3.5, 3.2
Find the:
(a) Mean
= 3.167
(b) Median
= 3.25
(c) Sum of squared deviations
= 0.533
(d) Variance
= 0.107
(e) Standard deviation
= 0.327
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, and 36 square feet.
(a) Figure the means and standard deviations for the governors and for the CEOs.
(b) Explain, to a person who has never had a course in statistics, what you have done.
(c) Note the 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.
Solution:
a)
Governors:
Mean= 43
Standard Deviation = 6.83
CEO's:
Mean= 44
Standard Deviation = 12.65
b)
Measuring the mean is finding the average size of the desk, It gives you a good idea
of the size of the desks, as long as the spread in sizes is small. The standard
deviation measures the spread in the sizes. If its large compared to the average
size, then the desks are all different sizes, but if its small, then they are all about the
same size: the mean size.
c)