The river is moving at 5 miles per hour. The river is 500 meters wide. A person can swim 15 miles per hour. Calculate the time it takes for the person to swim across to a point on the bank exactly opposite to his starting position and then back. Then calculate the time it takes for a person to swim upstream for 500 meters and then downstream for 500 meters back to his original starting position. Are these two times the same

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.