Question

8.9 Ask More People. In the 2016 presidential pre-election surveys, ABC/Post sampled 740 likely voters during October 10-13, 2016, and asked if they were planning to vote for Clinton, and then asked the same question of a sample of 1135 likely voters taken from October 22-25, 2016. However, in their last survey taken November 3-6, 2016, just before the election held on November 8, 2016, they asked this question of a sample of 2220 likely voters. Why do you ABC Post did this? you think

Answer 1

ABC/Post has increased the sample size of likely voters to reduce the standard error of sample estimate of proportion of voters who are planning to vote for Clinton. This will led to decrease in the margin of error for a given confidence level and thus increases the accuracy of the estimate of proportion of voters who are planning to vote for Clinton.