From a random sample from a normal population, we observed a sample mean of 84.5 and a sample standard deviation of 11.2, with a sample size of 16. The null hypothesis (HO) is that the population mean (u) is equal to 80, and the alternative hypothesis (Ha) is that the population mean is not equal to 80. Based on a significance level of 0.01, the test statistic is t = 1.61 and the p-value is 0.9356. Therefore, we do not reject the null hypothesis. There is not sufficient evidence to conclude that the mean is less than 80. The evidence against the null hypothesis is weak or non-existent.