Question

Finding x and E: A 90% confidence interval for a population mean is given as 38.2 < μ < 50.0. Round your answers to 1 decimal place.

(a) Calculate the sample mean. x =

(b) Calculate the margin of error.

Answer 1

Solution :

given that

Lower confidence interval = 38.2

Upper confidence interval = 50.0

  = (Lower confidence interval + Upper confidence interval ) / 2

= ( 38.2 +50. ) / 2

Sample mean = =44.1

Margin of error = E = Upper confidence interval -

= 50.0 - 44.1

Margin of error = E  =5.9