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Similarly, there is a 95% chance that the population mean age is between 22.6 and 28.5.
Compare this to our empirical result above of 22.8 to 28.2. We are, again, very close.
Homework Problems –6.2
1. Describe, in your own words, what a bootstrap distribution is and why we would want to
use one. Be sure to mention the logical process behind building one, as well as the
assumptions we are making when we do so.
2. What is a confidence interval Explain in your own words.
3. The following is a random sample of 10 labor costs associated with farming for civilian
consumers (in billions of dollars) since 1970.
Labor Costs (bill. $)
229.9 303.7
137.9 58.3
81.5 196.6
36.6 168.4
122.9 347.4
(SOURCE: Data randomly sampled from U.S. Statistical Abstract, Table 847)
a. Does the Central Limit Theorem apply for this data Why or why not
b. Using a bootstrap distribution, calculate a 95% confidence interval for , the true
population average labor cost.
c. In a complete sentence, interpret the real-world meaning of this value.
d. Using the bootstrap distribution and percentiles, how likely is it that a sample of
labor costs has a mean greater than $190,000,000,000
4. In Arizona, primarily the Phoenix Metropolitan area, the issue of red-light cameras used
to catch red-light runners and speeders was a prominent one for much of the early 2000‟s.
Many studies were carried out over this period of debate to determine whether or not they
were effective, and whether or not they used taxpayer money appropriately. Suppose the
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