What is the final step to be performed in the mathematical expression (ΣX)2?

What is the final step to be performed in the mathematical expression (ΣX)2?

• A. Square each score
• B. Add the scores
• C. Add the squared scores
• D. Square the sum of the scores

Answer: (D)

When you see (ΣX)2, the operation is to square the total sum of the X values. The parentheses show you first add all X’s together to get a single total, and the exponent 2 applies to that total. So you’re not squaring each X before adding (that would be ΣX2 or ΣX^2); you’re squaring the sum you obtain. For example, if X = 2, 5, 7, then ΣX = 14 and (ΣX)2 = 14^2 = 196. This is different from ΣX^2 = 2^2 + 5^2 + 7^2 = 78. Therefore, the final step is to square the sum.

When you see (ΣX)2, the operation is to square the total sum of the X values. The parentheses show you first add all X’s together to get a single total, and the exponent 2 applies to that total. So you’re not squaring each X before adding (that would be ΣX2 or ΣX^2); you’re squaring the sum you obtain. For example, if X = 2, 5, 7, then ΣX = 14 and (ΣX)2 = 14^2 = 196. This is different from ΣX^2 = 2^2 + 5^2 + 7^2 = 78. Therefore, the final step is to square the sum.