We want to test Ho: = 10 vs. H: 10 at = 0.05. A 95% confidence interval for u calculated from a given random sample is (9.8, 19.9). Based on this we O cannot make any decision at all because the distribution of the population is unknown. cannot make any decision at all because (9.8, 19.9) is a 95% confidence interval; what we needed is a 5% confidence interval. cannot make any decision at all because the value of the test statistic is not available. reject Ho. fail to reject Ho