17. A study in 1991 by the US National Center for Health Statistics provided a point estimate of 25 5% for the percentage of adult Americans who were currently smokers. The sample size was 42,000. Assuming that this sample has the charactenstics of a random sample. construct and interpret a 99% confidence interval for the proportion of the population who were smokers. (Note: When the sample size is very large, even confidence intervals with large confidence coefficients are narrow)