Based on a random sample of 50, a 95% confidence interval for the population proportion was computed. Holding everything else constant, which of the following will reduce the length of the confidence...

Extracted text: Based on a random sample of 50, a 95% confidence interval for the population proportion was computed. Holding everything else constant, which of the following will reduce the length of the confidence interval by at about a half? (CHECK ALL THAT APPLY): A. Quadruple the sample size. B. Double the sample size. C. Change the confidence level to 99.7%. D. Decrease the sample proportion by half. E. Change the confidence level to 67.3%.