An engineer working for a leading electronics firm claims to have invented a process for making longer-lasting LCD TVs. Tests run on 24 LCD TVs made with the new process show a mean life of 1725 hours...

An engineer working for a leading electronics firm claims to have invented a process for making longer-lasting LCD TVs. Tests run on 24 LCD TVs made with the new process show a mean life of 1725 hours and a standard deviation of 85 hours. Tests run over the last 3 years on a very large number of LCD TVs made with the old process show a mean life of 1538 hours.

a. Is the engineer correct in her claim? Use??
= 0.011 tail in making your decision.

b. If the engineer is correct, what is the size of the effect?