Simplify these expressions. If you get equivalent to:
Sa+b colour orange
3a+5b colour blue
3b or 3b- colour green
6b, 12b or b colour red​

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%