Question 9.16 (pg. 428)

(a) What assumption must be made in order for it to be appropriate to use the formula of this section to construct a confidence interval to estimate the proportion of all adult Americans that have seen or been with a ghost? Select an answer That the sample size is large enough to assume a normal distribution That the sample is less than 10% of the population That we have a random sample

(b) Construct a 90% confidence interval for the proportion of all adult Americans that have seen or been with a ghost. Enter your answer as two decimals separated by a comma. [Example: .1, .2].

(c) Would a 99% confidence interval be narrower or wider than the interval computed in part (b)? Select an answer Narrower The same Wider