Hello Class, The 90% confidence interval rounded from the sample data is { 2.5, 2.73 ) and the 99% confidence interval rounded is ( 2.43 | 2.5 ). This basically means that there is 90% confidence that the average diameter is between 2.3 and 2.73 centimeters and there is a 99% confidence rate that the average diameter is between 2.43 and 2.8 centimeters. The null hypothesiz is that the average diameter of ball bearings from this manufacturer are 2.30 centimeters. This hypothesizs would suggest that the diameter iz greater. Also considering that the 90% and 99% confidence interval levels are above 2.30 it 12 safe to assume that the diameter i3 greater than 2.30. The level of significance i3 01, which would indicate a 1% chance of a 2.30 centimeter diameter. The test-statistic = 4 81 and the two tailed p-value = 0.0. I would say that the null hypothesis should be rejected as the diameter of the ball bearing is averaging greater than 2.30 centimeters