A sample size must be determined for estimating a population mean given that the condence level is 90% and the desired margin of error is 0.21. The largest value in the population is thought to be 12 and the smallest value is thought to be 4. Calculate the sample size required to estimate the population mean using a generously large sample size. (Hint: Use the rangef6 option.) The sample size required is . (Round up to the nearest whole number as needed.)