A study was conducted to determine the mean cost to repair a mobile device. Assume that the population is normally distributed. A sample of 12 devices was randomly selected. The sample mean was $90.42 and the sample standard deviation was $33.61.

a. What is the point estimate of population mean?

b. To construct 95% confidence interval for population mean, find the degree of freedom.

c. To construct 95% confidence interval for population mean, find the critical value.

d. To construct 95% confidence interval for population mean, calculate the margin of error.

e. Construct 95% confidence interval for population mean.

f. Interpret the confidence interval in part e.