a. To calculate the probability of randomly selecting a person who will vote for Candidate 1 or 2, we need to add the number of supporters for Candidate 1 and Candidate 2 and divide it by the total number of people surveyed.
Total number of supporters for Candidate 1 and 2 = 250 (Candidate 1) + 1,250 (Candidate 2) = 1,500
Total number of people surveyed = 2,500
Probability = Total number of supporters for Candidate 1 and 2 / Total number of people surveyed
Probability = 1,500 / 2,500 = 0.6
Therefore, the probability of randomly selecting a person who will vote for Candidate 1 or 2 is 0.6 or 60%.
b. If 1,000 more voters are surveyed, we can assume that the distribution of supporters for each candidate remains the same. Therefore, if we add 1,000 more voters to the survey, we can expect the same proportion of supporters for each candidate.
Number of supporters for Candidate 3 and 4 = 450 (Candidate 3) + 550 (Candidate 4) = 1,000
If we add 1,000 more voters to the survey, we can expect the same ratio of support for Candidate 3 and 4. Therefore, out of the additional 1,000 voters, we can expect 450 of them to prefer Candidate 3 and 550 of them to prefer Candidate 4.