1. A sample of 144 cans of coffee showed that an average weight of 16 ounces. The standard deviation of the population is known to be 1.4 ounces.
a. Construct a 95% and 99% confidence interval for the mean of the population.
b. Discuss why CI intervals are different in part a depending on the confidence level.
2. The monthly incomes from a random sample of workers in a factory are shown below. Be aware that this is the standard deviation of the population unknown case.
Monthly Income (In $)
- 4000
- 5000
- 7000
- 4000
- 6000
- 6000
- 7000
- 9000
a. Compute the point estimate of population mean and the point estimate of the population standard deviation (in dollars)
b. Compute the margin of error (in dollars) at 95% confidence
c. Compute a 95% confidence interval for the mean of the population. Assume the population has a normal distribution. Give your answer in dollars.