2.15. Table 2.2 shows the result of the 2000 Presidential election and the predictions of several organiza- tions in the days before the election. The sample sizes were typically about 2000. The percentages for each poll do not sum to 100 because of vot- ers reporting as undecided or favoring another candidate.

(a) What factors cause the results to vary some- what among organizations?

(b) Identify the sampling error for the Gallup poll. TABLE 2.2 Predicted Vote Gore Bush Nader Poll Gallup 46 48 4 Harris 47 47 ABC 45 48 3 CBS 45 44 4 NBC 44 47 3 Pew Research 47 49 4 Actual vote 48.4 47.9 2.7 Source: www.ncpp.org/