The heights of women are normally distributed with a mean of 65 inches and a standard deviation of 3.5 inches. Use the 68-95-99.7% rule to approximate the percentage of females that are shorter than 61.5 inches. (Enter your answer as a percent without the percent sign)

When designed experiments are conducted in a public school systems, researchers typically choose a particular district, and randomly select classes (for example fourth grade students in that district). The experiment is then conducted using all the students in the selected classes. Which type of sampling scheme is implemented?