Question

Use the sample data and confidence level given below to complete parts (a) through (d)

In a study of cell phone use and brain hemispheric dominance, an Internet survey was e-mailed to 2625 subjects randomly selected from an online group involved with
ears. 1014 surveys were returned. Construct a 90% confidence interval for the proportion of returned surveys.
a) Find the best point estimate of the population proportion p.
n
(Round to three decimal places as needed.)
b) Identify the value of the margin of error E
EN
(Round to three decimal places as needed)
c) Construct the confidence interval.
D

(Round to three decimal places as needed)

Answer 1

Explanation:

Given x = 1014 n= 2625

The best point estimate of the population proportion p is the sample proportion. The sample proportion is the number of successes divided by the sample size

= 1014÷ 2625 = 0.3862

for confidence level 1 - α = 0.90 z value for 90% confidence = 1.645

=0.3862+1.645 √0.3862(1-0.3862)÷2625 = √0.2370÷ 2625 = 0.000305

= 0.0.3862 - 0.000305 = 0.3858

= 0.0.3862 + 0.000305 = 0.3865