Chapter 11.5, Problem 15E

a.

To determine

How many people need to be surveyed?

Answer to Problem 15E

The margin of error is $\frac{1000}{\sqrt{3}}$

Explanation of Solution

Given information : The question is

The sample of margin of error of about $\pm \frac{100}{\sqrt{n}}\%$

Calculation :

Margin of error

  $\begin{array}{l}\pm \frac{100}{\sqrt{n}}\%\\ \pm 3\%=\pm \frac{100}{\sqrt{n}}\%\\ 3\sqrt{n}=10000\\ \sqrt{n}=\frac{10000}{3}\\ n=\frac{100}{\sqrt{3}}\end{array}$

b.

To determine

To find : the sample size increase or decrease on part(a)

Answer to Problem 15E

The sample size increase

Explanation of Solution

Given information : the question is:

The margin of error is $\pm 2\%$

To have a margin of error as $\pm 2\%$ you should increase the sample size as according to the formula, they have an inverse relationship