8. 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 assumed to be a normal distribution.
(a) Compute the 90% confidence interval of the standard deviation (a) of distribution (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.