Statistics homework help please!

#1
A biologist has found the average weight of 12 randomly selected mud turtles to be 8.7 lb with standard deviation 3.6 lb. Find a 90% confidence interval for the population mean weight of all such turtles.

Rachel
 
#2
1. Try make some good assumptions to get nice theory work;

2. Check textbooks to learn how to get confidence interval for parameters involved in normally distributed random variables.