Question: The following quotes for cleaning cost have been obtained from a random sample of 12 providers chosen from a much larger population, prior to awarding a contract for these services:
$114, $154, $142, $132, $127, $145, $135, $138, $126, $142, $135, $124
a. Approximately how far is the average of these 12 quotes from the unknown mean for the entire population of providers?
b. Find the margin of error (for two-sided confidence at the 95% level).
c. Find the 95% confidence interval for the population mean quote.
d. Find the 99% confidence interval for the population mean quote.
e. Find the one-sided 95% confidence interval that claims that the population means quote is no larger than some value.
f. Find the one-sided 99% confidence interval that claims that the population means quote is no larger than some value.