Question 235546
a manufacture of tv tubes has for many years used a process giving a mean tube life of 4900 hrs and a standard deviation of 1200 hours.
--------------------------------------------------------------------
A new process is tried to see if it will increase the life significantly. 
A sample of 100 new tubes gave a mean life of 5000 hrs. 
--------------------------------------------------------------------
Is the new process better than the old process at 1% level of significant? Construct hypotheses test it and interpret the result.
---------------------
Ho: u = 4900
Ha: u > 4900 (claim)
-------------------------
Test statistic: t(5000) = (5000-4900)/[1200/Sqrt(100)] =1000/1200= 0.8333..
-------------------------------
p-value: P(t>0.8333 with df=99) = 0.2033
---------------------------------
Since the p-value is greater than 1% do not reject Ho.
The new process is not an improvement over the old process.
============================================================
Cheers,
Stan H.