A rods manufacturer makes rods with a length that is supposed to be 19 inches. A quality control technician sampled 40 rods and found that the sample mean length was 19.05 inches and the sample standard deviation was 0.25 inches. The technician claims that the mean rod length is more than 19 inches.

What type of hypothesis test should be performed? two-tailed t-test, two-tailed z-test, left-tailed t-test, or right-tailed t-test

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? yes or no?