Question 1: In a sample of 150 auto occupants, 86% wore seatbelts. In a sample of 200 truck occupants, 74% wore seatbelts. At "alpha" = 0.10, is there sufficient evidence to reject the claim that there is no difference in these proportions?
Question 2: Find the 90% confidence interval for the true difference in proportions for the data in problem above.
Question 3: Marty claims that the standard deviation of the weights of pre - 1964 quarters is the same as that for post - 1964 quarters. The standard deviation for 40 pre-1964 quarters is 0.08700 grams and for 40 post-1964 quarters it is 0.06194 grams. At "alpha" = 0.05, can we reject Marty's claim?