Answer Happy

To obtain information on the corrosion-resistance
properties of a certain type of steel conduit, 45 specimens are
buried in soil for a two-year period. The maximum penetration (in
mils) for each specimen is then measured, yielding a sample average
penetration of 52.7 and a sample standard deviation of 4.8. The
conduits were manufactured with the specification that the true
average penetration be at most 50 mils. They will be used unless it
can be demonstrated conclusively that the specification cannot be
met. What would you conclude? Use a significance level of
0.01.