Question

Express the confidence interval 0.319 < p < 0.488 in the form of p ± E.

( if i wanted to use my TI-84 calculator to find how to do this does anyone know what buttons I would need to use)

Answer 1

`0.4035+/-0.0845`

Explanation:

The fundamental step would be to determine the values of p and E which i believe is the margin of error in this case. Consider the following two equations;

`p-E=0.319\\p+E=0.488`

We simply add the two equations and solve for p;

`2p=0.807\\p=0.4035`

We then substitute this value of p in either equation and solve for E;

`0.4035-E=0.319\\E=0.0845`

Since we have both p and E, the confidence interval can thus be written as;

`0.4035+/-0.0845`