To calculate percentage, take the percent (17%) and take its decimal form. This means 17% is 0.17 (like 50% would be 0.5). multiply the number you want the percentage of by the decimal form. 13*0.17=2.21. Add this to the cost before tax and before tip. 13.00+2.21=15.21. The cost before tax with tip is $15.21.
Since the population is normally distributed, the sampling distribution of the sample mean will also be normally distributed, even when the sample size is small.
