margin of error

[brianne03]

This question seems so easy yet I can't seem to figure it out..

A simple random sample of 100 students who work part tiem or full time produced the 90% confidence interval for the mean earnings per week:

t-interval for u: with 90% CI, $286 < u < $304

- Find the margin of error for the interval

Thanks

 

[royhaas]

The margin of error is half the interval length.