Question

A random sample has been selected from a population. The point estimate = 78.65 and margin of error E = 8.24 for a 90% confidence level have been calculated for you. Construct the confidence interval that corresponds to this information.

Answer 1

Answer:

90% confidence interval: (70.41,86.89)

Step-by-step explanation:

We are given the following in the question:

Point estimate = 78.65

Margin of error, E = 8.24

Confidence level = 90%

Significance level = 10%

Formula:

$\text{Point estimate} \pm \text{Margin of error}$

Putting the values, we get,

$z_{critical}\text{ at}~\alpha_{0.10} = \pm 1.64$

$78.65 \pm 8.24 = (70.41,86.89)$

(70.41,86.89) is the required 90% confidence interval.