9. The length of each randomly selected dolphins in a super pod was measured: 14.6, 8.4, 21.1,
10.3, 9.4, 15.8, 8.0, 5.0, 15.4, 21.6, where the sample mean is 13.0 and sample standard
deviation is 5.6. The data is known to be a normal distribution.
(a) Do the hypothesis test to determine if the mean (u) of the distribution is greater than 12,
using the critical value method (assume the requirements for this procedure are met)
(b) List all of the requirements of this procedure
To receive full credits: Remember to show your work that explains each solution. Include all
relevant information, eg, hypotheses (if any), sample calculations, degree of freedom (if any),
critical values (if any), test statistic (if any), etc.