A researcher claims that the proportion of aggressive drivers in the US is 85%. To verify if this is true, a survey of 1100 drivers was conducted, and 990 admitted to aggressive driving during the past 6 months.

a. Construct and interpret a 95% confidence interval for the true proportion of all aggressive drivers in the US

b. Based on the confidence interval obtained in part (a), does the survey support the researcher's claim? Why or why not?

c. If we want to estimate the proportion to within 0.02 error at a 95% confidence level, how many drivers should we sample? Assume the true proportion is 0.85.