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 life time of the batteries may be shorter than the brand they currently in use. To test this, the new brand is installed in 8 randomly selected radios. Here are the results for the lifetime of the batteries (in hours).
45 5256 55 51 57 48 51
(A) Is the sufficient evidence to conclude that the purchasing manager is correct in his conjecture that the new brand has a shorter average lifetime?