Use the t-distribution to find a confidence interval for a difference in means 1-2 given the relevant sample results. Give the best estimate for 1-2, the margin of error, and the confidence interval. Assume the results come from random samples from populations that are approximately normally distributed.

A 99% confidence interval for 1-2 using the sample results x1=520, s1=128, n1=300 and x2=460, s2=88, n2=200

Enter the exact answer for the best estimate and round your answers for the margin of error and the confidence interval to two decimal places.