Sophie earns $12.80 per hour. she has to pay a loan to her parents in the amount of $100. after repaying the loan she wants to have at least enough money to buy sneakers for $130.40. write an inequality modeling the number of hours, x she needs to work to buy the sneakers

Arandom sample of 15 observations is used to estimate the population mean. the sample mean and the standard deviation are calculated as 172 and 63, respectively. assume that the population is normally distributed. a. with 99 confidence, what is the margin of error for the estimation of the population mean? b. construct the 99% confidence interval for the population mean. c. construct the 95% confidence interval for the population mean. d. construct the 83% confidence interval for the population mean. hint: you need to use excel function =t.inv.2t to find the value of t for the interval calculation.