الاحصاء الهندسي
ISE 325 Engineering Statistics Quiz Sample
- Bin Taleb Swimming Pool Manufacturing plant has noticed an increase
in warranty costs; service after sales. Most warranty failures are
caused by the main pump. It has been observed that the pump fails if
operated for an extended period of time. The industrial engineer has
identified 3 models of pumps they can import from Germany. The German
company has offered Bin Taleb a free no-obligation pumps to test. The
industrial engineer took 4 pumps from each model and let them ran to
failure; and he came up with the observations:
Observations Pump model 1 2 3 4 1 41 34 40 39 2 41 34 38 27 3 38 36 29 51 The observations represent the operation hours until failure. What can you say about the contribution of the pump model on the service duration? Maintain two decimal places.
Given:
- The industrial engineer believes that the production volume is
mainly influenced by two factors; feed rate and labor. He has
collected 9 observations as shown below:
Observation Production (units per hour) Feed rate (parts per hour) Labor (labor hours per hour) 1 257 68 2 2 348 92 6 3 329 58 12 4 336 65 11 5 388 66 16 6 381 77 13 7 319 63 9 8 385 69 15 9 256 65 3 
He assumes that a linear regression model will be adequate to explain the variability in the production.
- Compute the regression coefficients.
- Find the variance.
- Compute the variance of β1.
Note: retain all the digits given by your calculator (full digit computation).