Question

9. This problem using JMP refers to the Cars2015 dataset available on Canvas/Homework Materials page. For this problem, assume that the 110 cars in the dataset are a random sample of all cars produced in 2015. (Whether this is really a valid assumption is unclear.) You should turn in your answers along with any images from JMP that help explain you got them. The confidence intervals desired below can be produced under “Analyze→Distributions” and by clicking the red upside-down triangle in the resulting output window.

(a) Find a 95% confidence interval for the mean highway gas mileage (HwyMPG) for all cars produced in 2015.

(b) Find a 95% confidence interval for the proportion of 2015 cars that were midsized. (Refering to the Size variable in the dataset.)

Answer 1