A large number of people were shown a particular video of an automobile collision between a moving car and a stopped car. Each person then filled out a questionnaire about how likely it was that the driver of the moving car was at fault, on a scale from 0 = not at fault to 10 = completely at fault. The distribution of ratings under ordinary conditions follows a normal curve with μ = 5.5 and σ = .8. Sixteen randomly selected individuals are tested in a condition in which the wording of the question is changed so that the question asks, "How likely is it that the driver of the car who crashed into the other was at fault?" (The difference is that in this changed condition, instead of describing the event in a neutral way, the question uses the phrase "crashed into.") Using the changed instruction, these 16 research participants gave a mean at fault rating of 5.9. Did the changed instructions significantly increase the rating of being at fault?
(a) Carry out a Z test using the five steps of hypothesis testing (use the .05 level).
(b) Make a drawing of the distributions involved.
(c) Explain your answer to someone who has never taken statistics.
(d) Figure the 95% confidence interval.