Question

For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding.

In a marketing survey, a random sample of 986 supermarket shoppers revealed that 268 always stock up on an item when they find that item at a real bargain price.

(a) Let p represent the proportion of all supermarket shoppers who always stock up on an item when they find a real bargain. Find a point estimate for p. (Round your answer to four decimal places.)


(b) Find a 95% confidence interval for p. (Round your answers to three decimal places.)

lower limit
upper limit

Give a brief explanation of the meaning of the interval.

95% of all confidence intervals would include the true proportion of shoppers who stock up on bargains. 95% of the confidence intervals created using this method would include the true proportion of shoppers who stock up on bargains.     5% of all confidence intervals would include the true proportion of shoppers who stock up on bargains. 5% of the confidence intervals created using this method would include the true proportion of shoppers who stock up on bargains.

(c) As a news writer, how would you report the survey results on the percentage of supermarket shoppers who stock up on items when they find the item is a real bargain?

Report the confidence interval. Report the margin of error.     Report p̂. Report p̂ along with the margin of error.

What is the margin of error based on a 95% confidence interval? (Round your answer to three decimal places.)

Answer 1