A nutritionist wishes to investigate the mean sugar content in some cereal bars. He takes a random sample of 10 bars and measures the mass, of sugar in each bar. His results are as follows. 11.9 11.7 11.8 11.9 11.6 12.1 11.7 11.9 11.8 11.9 Calculate a 99% confidence interval for the population mean mass of sugar .