Hello! I have done the question but just need help with checking conditions and assumptions! I need to make sure it fits a nearly normal model by making a histogram. I made a histogram from the differences from the values. My histogram doesn't seem to match a normal model. How do I proceed if my conditions aren't met?

Here are the results (miles per gallon): Car # 2 3 4 5 6 7 8 9 10 Regular 16 20 |21 22 23 22 27 25 27 28 Premium 19 22 24 24 25 25 26 26 28 32 a) Is there evidence that cars get significantly better fuel econ- omy with premium gasoline? b) How big might that difference be? Check a 90% confidence interval. c) Even if the difference is significant, why might the company choose to stick with regular gasoline? d) Suppose you had done a "bad thing." (We're sure you didn't.) Suppose you had mistakenly treated these data as two independent samples instead of matched pairs. What would the significance test have found? Carefully explain why the results are so different