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) Construct a 75% confidence interval for the population proportion who claim they always buckle up and write the interpretation (Sketch the graph).

(b) Which distribution you used for this problem? Explain your choice.