20. A car company claims that their Super Spiffy Sedan averages 31 mpg. You randomly select 8 Super Spiffies from local car dealerships and test their gas mileage (MPG) under similar conditions. You get the following MPG scores: MPG: 30 28 32 26 33 25 28 30 Does the actual gas mileage for these cars deviate significantly from 31? (use alpha = 05) a. State the hypotheses of the study. b. Find the critical t value for this study. c. Compute the one-sample t test. (Again calculate sample SD or s to get SEM before calculating t.) d. Compute the Cohen's d for the data (even if not significant) e. State the results - is the sample significantly higher? Do you reject the null hypothesis? Report the t test results in APA format (include the numbers)