Variance of X (2e)

Once again, I extend the tabular approach used in the previous video (where we found the expected value), but in this case it is used to find the variance of x. The standard deviation of x is simply the square root of the variance (just like in Chapter 4).

Remember to make use of the order of operations:

1. (B)rackets … Subtract the mean μ from each x to get a list of (x-μ)
2. (E)xponents … Square each value of (x-μ) to get a list of (x-μ)²
3. (D)ivision … (no division here)
4. (M)ultiplication … Multiply each (x-μ)² by its corresponding P(x) to get a list of (x-μ)²P(x)
5. (A)ddition … Add up all (x-μ)²P(x) in the column to get ∑(x-μ)²P(x)
6. (S)ubtraction … (subtraction was in brackets, so it was handled in step 1)