If you wish to estimate a population mean with a sampling distribution error SE= 0.31 using a 95% confidence interval and you know from prior sampling that o2 is approximately equal to 6.4, how many observations would have to be included in your sample

Answer:

Given a=0.05, |Z(0.025)|=1.96 (from standard normal table)

So n=(Z*s/E)^2

=(1.96*6.4/0.31)^2

=1637.377

Take n=1638