A taxi company tests a random sample of 10 steel-belted radial tires of a certain brand and

Question:

A taxi company tests a random sample of 10 steel-belted radial tires of a certain brand and records the following tread wear: 48,000, 53,000, 45,000, 61,000, 59,000, 56,000, 63,000, 49,000, 53,000, and 54,000 kilometers. The marketing claim for the tires is that, on the average, the tires last for 53,000 kilometers of use. In your answer, compute

I - 53, 000 t = s/V10
and determine from Table A.4 (with 9 degrees of freedom) whether the computed t-value is reasonable or appears to be a rare event.