Lecture 1 - Quiz

Given:
Variance = 25
Coefficient of Variation = 10%

Compute the mean.

Answer:

We know the relationship between the coefficient of variation, standard deviation and the mean:
CV=(stddev/mean) * 100

We also know that the standard deviation is simply the square root of the variance:
Stddev = sqroot(variance)

Therefore, combining these two formulas and plugging in our givens, we get:
10 = (sqroot(25) / mean) * 100

10 = (5/mean) * 100

10 = 500 / mean

10 * mean = 500

mean = 50

The only thing tricky about this question is that you have to remember that the CV is stddev/mean, not variance/mean. If you remember that, along with the relationship between the stddev and variance, it's simple.