Statistics I
Professor Nie
Homework Assignment 3
Recitation Tuesday 2:00 – 3:15
Section 32: 2, 6, 8, 10, 16, 20
2. The median does a better job because the professor is an outlier, skewing the mean of the
group. The median is not affected very much by the outlier because the middle value still falls on
one of the nonextreme values.
6. Mean: 29.7
Median: 34.5
Mode: 47
Midrange: 25
The mean is not a good estimate because of the skew produced by factoring in outliers like “3”
that are not representative of the population. The median would be much better at serving as a
representative value of the sample.
8.Mean:91.3
Median: 93.5
Modes: 98, 95, 92
Midrange:
81.5
The standard deviation is 8.9. The value 65 appears to be an outlier, since it is outside of three
standard deviations from the mean. If I exclude it and calculate the mean, I get a mean of 93.6,
and a standard deviation of 3.3 minutes. My prediction is 94 minutes. There is a 68% chance that
in a normal distribution, a measurement will lie within 1 standard deviation, 3.3 minutes. The
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 Spring '08
 Hall
 Normal Distribution, Standard Deviation, Mean, standard deviations

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