health insurers and the federal government are both putting pressure on hospitals to shorten the average length of stay (los) of their patients. in 2003, the average los for non-heart patients was 4.6 days. a random sample of 20 hospitals in one state had a mean los for non-heart patients in 2008 of 3.8 days and a standard deviation of 1.2 days and is normally distributed. calculate a 95 percent confidence interval for the population mean los for non-heart patients in these hospitals in 2008.