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 2580 subjects randomly selected from an online group involved with ears 975 surveys were returned Construct a90% confidence interval for the proportion of returned surveysClick the icon to view a table of z scoresa) Find the best point estimate of the population proportion p0 378(Round to three decimal places as needed)b) Identify the value of the margin of error EE E-(Round to three decimal places as needed)

Answer 1

Solution

The point estimate is the best guess and that is 975/2580 or 0.378

the half-interval is z(0.95), for two sided confidence interval, * sqrt (p*(1-p)/n); the sqrt term is the standard error of the me975