Variability Question

Question

   Is it possible to obtain a negative value for the variance or standard deviation?

Answer 1

No. To calculate variance we add up the squares of the differences of our data from the mean, and divide by (n-1) or (n). These squares must all be zero or positive, so the variance has to be zero or positive.

Standard deviation is the positive square root of the variance, so that also has to be zero or positive.

Mike