1) The Gallop Poll folks found that 27% of adult's surveyed (national survey) said that they had been in a tornado. How many adults would need to be surveyed to estimate the true proportion with a 95% confidence that is 5% wide?
2) A recent study indicated that 29% of 100 women over age 55 in the study were widows.
a) How large a sample must one take to be 90% confident that the estimate is within 0.05 of the true proportion?
b) If no estimate of the sample proportion is available, how large a sample is needed?
3) An old study of 1000 people in Phoenix found that 27 were obese. Find the 99% confidence interval of the population proportion of persons living in Phoenix who are obese.