Question

A population has a standard deviation of 50. A random sample of 100 items from this population is selected. The sample mean is determined to be 600. At 95% confidence, the margin of error is

Answer 1

Given :

Standard deviation of population = 50

Number of items = 100

Confidence = 95%

Sample mean = 600

To Find :

The margin of error

Solution :

• Error = (z×σ) /√n

        = 1.96 × 50 /√100

        = 9.8

• Margin of error = ( 600-e , 600+e)

              = ( 600-9.8 , 600+9.8)

              = (590.2 , 609.8)

The margin of error is  (590.2 , 609.8)