A study rated various brands of peanut butter on how creamy they were. The study used 4 different brands, found a sample mean of 17, and a sample standard deviation of 1.

We wish to construct a 99% confidence interval for these findings.

1. How many degrees of freedom do we have?
2. To construct this confidence interval, what type of test should we use?1, 2, or 3 tail t test
3. If we wish to use an alphaalpha of 0.01, the value of t_crit is
4. Calculate Calculate X_+(sX_)(tcrit) using only the positive value of t_crit.
5. How do we present our confidence interval?