The maximum wind speeds (in knots) of 13 randomly selected hurricanes that have hit the U.S. mainland are listed. Use a 95% level of confidence. 

70   85   70   75   100   100  110   105   130   75   85   75    70

Assume the sample is from a normally distributed population and construct the indicated confidence intervals for 

(a) The population variance σ² and 

(b) The population standard deviation s. Interpret the results.