A local television channel wishes to give an estimate of the proportion of voters in favor of candidate "A" during a municipal election. It turns out to be too expensive to select and interview an SRS of voters, so the channel opted for a cluster sampling, using districts as clusters. An SRS of 9 districts is selected among the 503 districts of the city. The broadcaster wants to make the estimate on election day, but before the final results are tallied. Reporters are then sent to the polling stations in each selected districts to obtain the relevant information, presented below : District 1 2 3 4 5 6 7 8 9 Voters i 1290 1171 1170 1066 840 843 1893 971 1942 In favor of candidate "A" yi 680 596 631 487 475 321 1143 542 1187 Determine a C.I. for the proportion of voters in the city who favor candidate "A", at approximately 95%. How many quarters should be sampled in order to obtain a margin of error on the estimate B = 0.03