In a sample of n=9 lichenspecimens, the researchers found the mean and standard deviation of the amount of the radioactiveelement, cesium-137, that was present to be 0.009 and 0.005 microcurie permilliliter, respectively. Suppose the researchers want to increase the sample size in order to estimate the mean to within 0.001 microcurie per milliliter of its truevalue, using a95% confidence interval.

a. Compute the sample size necessary to obtain the desired estimate.