The first one is 2.78% second one is 3.8% third one is 4.5% and it will be 378
35% of 98 is 34.3
Change the percentage (35) into a decimal by dividing over 100:
35 / 100 = 0.3
Multiply the decimal and 98:
0.35 × 98 = 34.3
The predicted value of hardness at 37 hours is 243.87 and an 85% confidence interval for the mean hardness is (242.12, 245.61). At 41 hours, the predicted hardness is 252 and an 85% confidence interval for mean hardness is (249.83, 254.18). The confidence interval for X is equals to 41 which is wider because the value 41 is farther away from the sample mean X than is 37. As an outcome, the standard error for the prediction is larger.
