There are four presidential candidates in a country. A street survey was

conducted asking 2,500 registered voters which candidate they will vote for in
the coming election. The table summarizes the results of the survey.
candidates supporters
Candidate 1 250
Candidate 2 1,250
Candidate 3 450
Candidate 4 550
a. What is the probability of randomly selecting a person who will vote for candidate 1 or 2?
b. If 1,000 more voters are surveyed, how many of them will likely prefer candidate 3 or 4? Explain the answer.

1 answer

a. To find 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 then divide by the total number of voters surveyed.

Total supporters for candidate 1 and 2 = 250 + 1250 = 1500
Total voters surveyed = 2500

Probability = Total supporters for candidate 1 and 2 / Total voters surveyed
Probability = 1500 / 2500
Probability = 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 proportion of voters preferring candidate 3 or 4 remains the same. In that case, we can find the expected number of voters who will prefer candidate 3 or 4 by using the proportions from the initial survey.

Proportion of voters preferring candidate 3 = 450 / 2500 = 0.18
Proportion of voters preferring candidate 4 = 550 / 2500 = 0.22

Expected number of voters preferring candidate 3 in the additional 1,000 surveyed = 0.18 * 1000 = 180
Expected number of voters preferring candidate 4 in the additional 1,000 surveyed = 0.22 * 1000 = 220

Therefore, if 1,000 more voters are surveyed, it is expected that 180 voters will prefer candidate 3 and 220 voters will prefer candidate 4.