申論題

7. An equipment manufacturer has developed a new electrical product. He
claims that the product has a mean life length of 10,000 hours, with a standard
deviation of 150 hours. A consumer tested 16 random samples of the product
and obtained a mean life length of 9,775 hours. Evaluate at the 0.05 level of
significance whether the life length announcement for the new product is
reliable ? (12%)