Compute the variance for x:

Question

Number of Times          Owner Occupied
0                              439   
1                              1100
2                              249
3                              98
4 or more                      120
Total                          2006

I'm really struggling with this one, any help would be greatly appreciated! I also know that E(x)= 1.18, but don't know how to compute variance.

My professor wrote $Var(x) = E(x²) – [E(x)]² = 6.7 – (1.18)² = 5.30$

But I do not know how to get 6.7 I know that it is the summation of all $x^2f(x)$, but I keep on getting 2.44

I did $0+0.55+0.48+0.45+0.96$

Answer 1

Given what you've posted here, your professor's calculation of $\mathbb E[X^2] = 6.7$ does indeed appear to be incorrect.