Marco’s bank statement says that he has an ending balance of $81. What is Marco’s starting balance?

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%

Joanie watched 1 out of three of a movie in the morning

Me i’m stuck on all these questions besides the two bottom ones