Use the following sample to estimate a population mean g. 40.9 88 49.6 29.6 68.8 81.1 52.6 90.3 78.5 80 40.4 Assuming the population is normally distributed, find the 99.9% confidence interval about the population mean. Enter your answer as an open-interval (i.e., parentheses) accurate to two decimal places. 99.9% C.I. =