An admissions officer is trying to choose between two method

An admissions officer is trying to choose between two methods of predicting first-year scores. One method has an r.m.s error of 10. The other method has an r.m.s. error of 5. Other things being equal, which method should he choose? Why?

Solution

He should choose the one with lower rms error, rms = 5.

This is because for the same (everything, like sample size), he will yield a less margin of error.