For the hypothesis test, we need to find the test statistics
t = (x-bar - Mu)/standard error
standard error = sample standard deviation/square root of n
From here we compare the test statistic to the critical value t or you can compute the p-value and compare to alpha level of the test at .05
If the p-value < alpha, then reject Ho. Notice in the case of your problem, there is a rejection of the null hypothesis in both cases.
For the confidence interval it's mean +/- tcritical*standard error.