Question

I need help with this question. There are more parts to it. I think a,b,c, d, and e. This is part a. Thank you.

Construct a confidence interval of the population proportion at the given level of confidence. X = 860, n = 1200, 94% confidence Click here to view the standard normal distribution table (page 1) Click here to view the standard normal distribution table (page 2). . The lower bound of the confidence interval is (Round to three decimal places as needed.)

Answer 1

Solution :

Given that,

Point estimate = sample proportion = $\hat p$ = x / n = 860 / 1200 = 0.717

1 - $\hat p$ = 1 - 0.717 = 0.283

Z$\alpha$ = 1.555

Margin of error = E = Z$\alpha$  * $\sqrt$ (($\hat p$ * (1 - $\hat p$ )) / n)

= 1.555 * ($\sqrt$((0.717 * 0.283) / 1200)

= 0.020

The 94% lower bound of the confidence intarval P is ,

$\hat p$ - E

0.717 - 0.020

0.697

The lower bound of the confidence intarval is 0.697