Expression in terms of X for the variance

[Turkish]

1. 'Find an expression in terms of x for the variance of: 9,4,x,3'
Give your answer in the form of ax^2 + bx + c

I would usually give you some information of how I could possibly tackle this question but unfortunately I have no idea. Could someone shed some light? Thanks

 

[arildno]

Well, given four numbers, 9,4, BLOING,3, how would you normally calculate the variance related to this set of numbers?

 

[Turkish]

well I'd use the statistical formula for variance
Variance = Sum of (x - xbar)^2 / n

 

[arildno]

So, what is the average value, xbar, with the numbers that have been given you?