Chapter 4.5, Problem 20E

In Exercises $9-22$, round off your answers (sample proportions and margins of error) to three decimal places (a tenth of a percent).

Exercises $17-20$ are based on a survey (published in April 2000) of 129, 593 students in grades 6-12 conducted by USA WEEK-END magazine.

When asked, "How likely do you think it is that a major violent incident could occur at your school?" 18, 143 said very likely, 64, 797 said somewhat likely, and 46, 653 said not likely at all.

a. Determine the sample proportion of students who said "very likely."

b. Determine the sample proportion of students who said "somewhat likely."

c. Determine the sample proportion of students who said "not likely at all."

d. With a $90\%$ level of confidence, find the margin of error associated with the sample proportions.