Consider the accompanying data on breaking load (kg/25mm width) for various fabrics in both an unabraded condition and an abraded condition.

Fabric
1 2 3 4 5 6 7 8
U 36.4 55.0 51.5 38.7 43.2 48.8 25.6 49.8
A 28.5 20.0 46.0 34.5 36.5 52.5 26.5 46.5

a. Test if the average breaking load of various fabrics in unabraded condition is greater than that in abraded condition using the rejection method at significance level 0.01.
b. Compute a 99% confidence interval for the true average difference of breaking load for fabric in unabraded and abraded condition.