1)
Measures of dispersion tell us about the size and spread of a data set whereas
skewness tells us about the shape of a distribution of data.
2)
a.
Book Value
Earnings
population mean=
20.15143
2.838571
population standard deviation=
5.915267
0.447929
coefficient of variance=
0.293541
0.157801
Because the coefficient of variance of the book value is greater than that of
the earnings, the book value is more variable.
b.
Book Value
Earnings
zscore
0.851791
0.650613
Because the zscore of the book value is higher than that of the earnings, the
book value of Con Ed is relatively further from the mean than the earnings.
3)
a.
Bat dog:
0.92582
No Country for Old Statisticians:
1.38873
Indiana Smith Meets Godzilla:
0.46291
b.
as with all sets of zscores, the mean is 0 and standard deviation is 1
4)
a.
16%
b.
2.5%
c.
34%
d.
81.5%
5)
a.
2 standard deviations: 75%
3.5 standard deviations: 91.84%
b.
2 standard deviations: 95%
3 standard deviations: 99%
6)
a.
This distribution is negatively skewed because the median and mode are less
than the mean.
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 Spring '08
 ROBERTJ.THORNTON
 Standard Deviation, standard deviations, George Snooze

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