Frazier Powell

05/20/2023 · Middle School

A manufacturer must test that his bolts are 1.00 cm long when they come off the assembly line. He must recalibrate his machines if the bolts are too long or too short. After sampling 64 randomly selected bolts off the assembly line, he calculates the sample mean to be 1.05 cm . He knows that the population standard deviation is 0.18 cm . Assuming a level of significance of 0.05 , is there sufficient evidence to show that the manufacturer needs to recalibrate the machines? Step 3 of 3: Draw a conclusion and interpret the decision. Answer 2 Points We reject the null hypothesis and conclude that there is sufficient evidence at a 0.05 level of significance that the mean length of the bolts is different from 1.00 cm and the machines need to be recalibrated. We reject the null hypothesis and conclude that there is insufficient evidence at a 0.05 level of significance that the mean length of the bolts is different from 1.00 cm and the machines need to be recalibrated. We fail to reject the null hypothesis and conclude that there is sufficient evidence at a 0.05 level of significance that the mean length of the bolts is different from 1.00 cm and the machines need to be recalibrated. We fail to reject the null hypothesis and conclude that there is insufficient evidence at a 0.05 level of significance that the mean length of the bolts is different from 1.00 cm and the machines need to be recalibrated.