A Company Provides Portable Walkie-Talkies to Construction Crews $$\begin{array} { l l l l l l l l } 45 & 52 & 56 & 55 & 51 & 57 & 48 & 52\end{array}$$

Essay

A company provides portable walkie-talkies to construction crews. Their batteries last, on
average, 55 hours of continuous use. The purchasing manager receives a brochure
advertising a new brand of batteries with a lower price, but suspects that the lifetime of the
batteries may be shorter than the brand currently in use. To test this, 8 randomly selected
new brand batteries are installed in the same model radio. Here are the results for the
lifetime of the batteries (in hours): $$\begin{array} { l l l l l l l l } 45 & 52 & 56 & 55 & 51 & 57 & 48 & 52\end{array}$$ Is there sufficient evidence to conclude that the purchasing manager is correct in his
conjecture that the new brand has a shorter average lifetime?