Confidence interval for true population proportion and sample size.
1) In a recent survey of 150 households, 54 had central air conditioning. Find a 96 percent confidence interval for the true percentage of all households that have central air conditioning. Write down a sentence that interprets this interval.
2) A researcher wishes to estimate, with 95 percent confidence, the proportion of people who own a home computer. A previous study shows that 40% of those interviewed had a computer at home. Find the least amount sample size necessary if the researcher wants to be accurate within 2% of the true proportion.