A test of writing ability is given to a random sample of 11 students before and after they completed a formal writing course. The results are given below: Before: Mean = 80.27, standard deviation =...

A test of writing ability is given to a random sample of 11 students before and after they completed a formal writing course. The results are given below:

Before: Mean = 80.27, standard deviation = 12.76

After: Mean = 78.27, standard deviation = 12.92

Before/After: Mean = 2, standard deviation = 2.65

Construct a 99% confidence interval for the mean difference
between the before and after scores.

Round your answer to 3 decimal places.