1. A survey is to be conducted to study work absence due to acute illness in a factory with 1200 workers. Suppose the mean number of days lost per year is 4.6 and that the standard deviation is 2.7 days lost per year, and the sample is to be selected by simple random sampling. What sample size is needed to produce an estimate of the mean number of days lost with a standard error () of 0.15? 2. A population of N = 10,000 farms has a variance for annual crop yield of $2 = 1,000,000. Calculate the simple random sample size needed to obtain a standard error for the mean annual crop yield of :1,000. 3. A sample of n = 10 was selected by simple random sampling from a list of 12,000 registered voters in a city. Each household where the sample registered voters lived was visited and information collected on whether the household had central air conditioning. Estimate the percentage of registered voters living in households with central air conditioning. (Since Case number 5 is missing, please use n=9) Case Number Number of Registered Voters Air Conditioning Indicator Present Absent UJ Present Present Absent Absent Absent 9 Present 10 4 Present 4. For situation in 3 above, estimate the percentage of households with central air conditioning. 5. Briefly explain in words the relationship between the nonresponse rate and the bias of nonresponse for an estimate of the population mean