Assume that a sample is used to estimate a population mean . Find the margin of error M.E. that corresponds to a sample of size 18 with a mean of 27.6 and a standard deviation of 20.4 at a confidence level of 99.9%. Report ME accurate to one decimal place because the sample statistics are presented with this accuracy. M.E. = Answer should be obtained without any preliminary rounding. However, the critical value may be rounded to 3 decimal places.