A rods manufacturer makes rods with a length that is supposed to be 20

inches. A quality control technician sampled 27

rods and found that the sample mean length was 20.08

inches and the sample standard deviation was 0.16

inches. The technician claims that the mean rod length is less than 20

inches.

What type of hypothesis test should be performed?

What is the test statistic?

What is the number of degrees of freedom?

Does sufficient evidence exist at the =0.1

significance level to support the technician's claim?

Select

Left-tailed t-test

Left-tailed z-test

Right-tailed t-test

Two-tailed t-test

Select

No

Yes

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