Question

Assume that a sample is used to estimate a population proportion

p.

Find the margin of error E that corresponds to the given statistics and confidence level.

​95% confidence;

nequals=​2388,

xequals=1672

Answer 1

Solution :

Given that,

n = 2388

x = 1672

Point estimate = sample proportion = = x / n = 1672/2388=0.700

1 -   = 1-0.700 =0.300

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z/2 = Z0.025 = 1.96   ( Using z table )

Margin of error = E = Z / 2    * ((( * (1 - )) / n)

= 1.96 (((0.700*0.300) /2388 )

E = 0.0184

Margin of error = E =0.0184