Question 194063: My company has a fleet of 700 buses and 140 rail cars for urban mass transit
We repair everything ourselves. Recently we decided to try a Lean Manufacturing approach and try to optimize a standard engine rebuild that we do.
Our history data on the rebuild ( Same engine in all cases ) population mean was 34 hours with a 8 hour standard deviation.
After applying lean manufacturing principles on our rebuild team, we waited a few weeks for the "new" way to settle in then we retested to see if the times changed statistically
We sampled 30 jobs randomly and found a sample mean of 31 hours
Test at the 0.05 alpha, 2 tail test to see if we made statistical improvement 0.05 = 1.96
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! My company has a fleet of 700 buses and 140 rail cars for urban mass transit
We repair everything ourselves. Recently we decided to try a Lean Manufacturing approach and try to optimize a standard engine rebuild that we do.
Our history data on the rebuild ( Same engine in all cases ) population mean was 34 hours with a 8 hour standard deviation.
After applying lean manufacturing principles on our rebuild team, we waited a few weeks for the "new" way to settle in then we retested to see if the times changed statistically
We sampled 30 jobs randomly and found a sample mean of 31 hours
Test at the 0.05 alpha, 2 tail test to see if we made statistical improvement 0.05 = 1.96
---------------
Ho: u(old method) - u(new method) = 0
H1: u(old method) - u(new method) > 0
-----------------
t(34-31) = 3/sqrt[(8^2/840 + ?^2/30)] = ?
----------------------------------------------
Comment: You did not post the standard deviation of the sample of 30.
------------------------------------------------
Cheers,
Stan H.
|
|
|
