Question

3452 students were polled asking who they supported for student body president, 37% support Jill Steins. 35% support Gray Johnson. The additional 28% is spread out among 42 other 3rd party candidates none of which are polling greater than 2%.

Working with a 95% confidence level, estimate the margin of error.

Answer 1

Solution:

Formula for margin of error is given as below:

Margin of error = Z* sqrt(P*(1 – P)/n)

We are given

Confidence level = 95%

So, critical Z = 1.96

(by using z-table)

First margin of error for the proportion of students who support Jill Steins is given as below:

P = 0.37, n = 3452

Margin of error = 1.96*sqrt(0.37*(1 - 0.37)/3452) = 0.016106153

Margin of error =0.0161

Now we have to find the margin of error for the proportion of the students who support Gray Johnson.

P = 0.35, n = 3452

Margin of error = 1.96*sqrt(0.35*(1 - 0.35)/3452) = 0.015911509

Margin of error = 0.0159