a) The population standard deviation for the age of college students is 6.5 years. If we want to be 98% confident that the mean age has a margin of error of at most 2 years, how many college students must be surveyed?
b) A pollster wants to construct a 95% confidence interval for the proportion of adults who believe that economic conditions are getting better. A Gallup poll estimates the sample proportion to be 0.34. Using this estimate, what sample size is needed so that the confidence interval will have a margin of error of 0.03?