Discussion:
Q: State DMV records indicate that of all vehicles undergoing emissions testing during the previous year, 70% passed on the first try. A random sample of 200 cars tested in a particular country during the current year yields 156 that passed on the initial test. Does this suggest that the true proportion for this country during the current year differs from (i.e. is not equal to) the previous statewide proportion? Test the relevant hypotheses using alpha = 0.05.