1--- Voters in a particular city who identify themselves with one or the other of two political parties were randomly selected and asked if they favor a proposal to allow citizens with proper license to carry a concealed handgun in city parks. The results are:

	Party A	Party B
Sample size	150	200
Number in favor	90	140

a) (10 pts) Test, at the 10% level of significance, the hypothesis that the proportion of all members of Party A who favor the proposal is different from the proportion of all members of Party B who do.

b) (5 pts) Construct the 90% confidence interval for the difference of the two populations proportions.