Sigma Notation Part 2

In the previous step, we learned that (Sigma) is a basic instruction that tells you to add up data. Let’s take our knowledge of (Sigma) one step further.

The basic notation is:
(Sigma , ( , , ))

However, we could also have other operations within the parentheses (brackets) that follow Sigma.

Remember that in Maths we follow the correct order of operations in order to calculate something. We always begin with parentheses, so we have to first complete the operation in the parentheses before we perform the sum, which Sigma is instructing us to do.

Using this example of the table of ages:

Let’s perform this operation:
(Sigma (x – 1))

This is telling us to first subtract (1) from each age before we add up the data set.
(Sigma (x – 1) = (30 – 1) + (21 – 1) + (59 – 1) + (45 – 1))
(therefore Sigma (x – 1) = 29 + 20 + 58 + 44)
(therefore Sigma (x – 1) = 151)