Records on a Fleet of Trucks Reveal That the Average

question 69

Multiple Choice

Records on a fleet of trucks reveal that the average life of a set of spark plugs is normally distributed with a mean of 35,600 kilometres. A manufacturer of spark plugs claims that its plugs have an average life in excess of 35,600 kilometres. The fleet owner purchased 18 sets and found that the sample average life was 37,700 kilometres, the sample standard deviation was 2415 kilometres and the computed t = 3.677.

• A) Based on these findings, there is enough evidence to accept the manufacturer's claim at the 0.05 level.
• B) Based on these findings, there is NOT enough evidence to accept the manufacturer's claim at the

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Definitions:

Test Statistic

A calculated value used in hypothesis testing that helps to determine whether to reject the null hypothesis.

Pooled Variance

Pooled variance is a method used to estimate the variance of two or more groups by combining their variances, assuming they have the same variance but not necessarily the same mean.

Degrees Of Freedom

The number of independent values or quantities which can vary in an analysis without breaking any constraints.

Mean Score

A mean score represents the average outcome derived from a set of scores, reflecting the central tendency of the data.