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2. Answers vary
3.
a. No, the sample size is 10, which is less than the minimum required (30).
b. ( )
c. We are 95% confident that the population average labor cost is between $109.6
billion and $227.6 billion.
d. About 0.213
4.
a. Yes, since they can be 95% confident that the average revenue per camera will be
between $654.51 and $752.44.
b. No, since they can be 99% confident that the average revenue per camera will be
between $637.42 and $768.01, which includes the possibility of the average being
lower than $640.
c. Yes, the sample size is 30, which is the minimum required sample size for the
CLT results to be applied.
d. We know that , ̅- , which we are estimating by ̅. That is, we are assuming
the sample mean is the population mean for the basis of our interval. Here,
̅ . Similarly , ̅- √ . We are using to estimate . Thus, our
estimate of , ̅-
. Using our probability calculator, we find:
√
Our 95% confidence interval would be 652.1 to 755.1, which is close to our
bootstrap confidence interval. It is a bit wider than we would like.
e. Here we have that . We have 5% to split between the tails.
Thus, in each tail. We find that (same number of standard
deviations from the mean to each tail, since the distribution is symmetric):
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