Question

When a production machine is properly calibrated, it requires an average of 28 seconds per unit produced, with a standard deviation of 3 seconds. For a simple random sample of n = 50 units, the sample mean is found to be 25.2 seconds per unit.

(1) Calculate the Z-Score for this problem.

(2) Does the machine appear to be operating normally or should it be re-calibrated?

Answer 1

Average (4) = 28 seconds standard deviation (1) = 3 seconds sample size (m) =50 sample mean (x) = 25.2 € z-score = x-M s) 2 25-2- 7-score = -6.599 due to the sample size in is greater than 30 distribution can be assumed as the sampling normal distribution so the machine appear to be operating namally or for the z score of -1.96 less than and a score greater than 1.96 assumed to be unusual ѕ tо mасh in Can not bе opers a m., 4- Scanned with, ls braced . CamShoulde be recalibrated .