A Confidence Interval for A Population Proportion · Exercise 35

Suppose that the insurance companies did do a survey. They randomly surveyed 400 drivers and found that 320 claimed they always buckle up. We are interested in the population proportion of drivers who claim they always buckle up.

(a) (a) x = __________
(b) n = __________
(c) p′ = __________
(b) Define the random variables X and P′, in words.
(c) Which distribution should you use for this problem? Explain your choice.
(d) Construct a 95% confidence interval for the population proportion who claim they always buckle up.
(a) State the confidence interval.
(b) Sketch the graph.
(e) If this survey were done by telephone, list three difficulties the companies might have in obtaining random results.

Its source prints no answer for this problem, so there's nothing to check against.

OpenStax, Introductory Business Statistics 2e · §8.3 A Confidence Interval for A Population Proportion · Exercise 35