The president of a large university wishes to compare to standard deviation of the ages of students presently enrolled to previous years. The distribution of ages has been approximately normal. Find the 90% confidence interval for the population standard deviation of the students ages of the University. A random sample of 20 university students has a standard deviation of 6.1 years in a mean of 23.8 years. What is the confidence interval of the population standard deviation? Please show all your steps and if you use a calculator shortcut please state how you entered it into the calculator as I'm really trying to learn how to use, it thank you so much