Question

How do I solve this STATS question?

Answer 1

We have the following data:

Margin of Error = E = 2.7 % = 0.027
Sample size = n = 900
Proportion of adults in favor = p = 60% = 0.6

We need to find the confidence level. For this first we need to find the z value.

The margin of error for a population proportion is given as:

$E=z* \sqrt{ \frac{p(1-p)}{n} }$

Using the values, we get:

$0.027=z* \sqrt{ \frac{0.6*0.4}{900} } \\ \\ 0.027=z*0.016 \\ \\ z= \frac{0.027}{0.01633} \\ \\ z=1.65$

As, seen from the z table, z=1.65 corresponds to the confidence level 90%. So, the answer to this question is option B