Chapter 7, Testing difference between means. Help solve showing work?

40. A national polling organization conducts a telephone survey of American adults concern- ing whether they believe the president is doing a good job. A total of 990 persons surveyed had voted in the previous presidential election. Of the 630 who had voted for the president 72% said they thought he was doing a good job. Of the 360 who did not vote for the presj- dent, 60% reported that they thought he was doing a good job. Test the null hypothesis of no difference in population proportions who believe the president is doing a good job (use a .05 level of significance)