Tractor rollover protection. Refer to the Human Factors (February 2020) study on the incorrect usage of installed foldable rollover protection structures (FROPS) on tractors, Exercise 11.23 (p. 659). Recall that one common problem is incorrectly setting the vertical distance from the FROPS pivot pin to the top of the FROPS when in an upright position. This distance (in millimeters) was recorded for each of the 20 farmers as well as the farmer’s working experience (in years), and the data saved in the file. Do the data provide sufficient evidence of a positive linear association between a farmer’s experience and FROPS pivot pin-top distance?

a. Answer the question using a statistical test of hypothesis with a = .05.

b. Answer the question using a 95% confidence interval.