Now that we understand how to work with an operation inside the parentheses after (Sigma), let’s take it to the next step.

In maths, we always follow the order of operations. Here’s a reminder of the order for you:

Parentheses
Exponents
Multiplication / Division
Addition / Subtraction

Using this example of the table of ages:

Let’s perform this operation:
(Sigma (2x – 1))
(therefore Sigma (2x – 1) = (2 times 30 – 1) + (2 times 21 – 1) + (2 times 59 – 1) + (2 times 45 – 1))
(therefore Sigma (2x -1) = (60 – 1) + (42 – 1) + (118 – 1) + (90 – 1))
(therefore Sigma (2x – 1) = 59 + 41 + 117 + 89)
(therefore Sigma (2x – 1) = 306)

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Why is it important to follow the correct order of operations when applying statistical formulas.

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