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Mathematics 107 statistics problems
due Wednesday, May 15, 2013
1. Create data sets for which
• mode < median < mean
• mean <mode < median
2. To the right is a chart of ages of death in the U.S.
in 2006.
• draw a histogram of the ages
• estimate the mode age
• estimate the median age
age x
number (thousands)
0 ≤ x < 20
54
20 ≤ x < 40
95
40 ≤ x < 60
370
60 ≤ x < 80
836
80 ≤ x < 100
1052
100 ≤ x < 120
19
• by using midpoints, estimate the mean age
• by using midpoints, estimate the standard deviation of the ages
3. A set of measurements of the length of an infant is normally distribued, with a mean of 21
inches, and a standard deviation of 0.4 inches. Calculate the probability that a measurement
is between 20.8 and 21.4 inches.
4. A pollster wants to construct a 95% confidence interval for the percentage of people who
think that global warming is a major issue. If the pollster wants a margin of error less than
2%, how many people should be polled ?