Samantha made a mistake in the way she structured her formula for calculating the average. The formula she entered in cell B6 is:
=B2 + B3 + B4 + B5 / 4
In this formula, the division by 4 only applies to the value in cell B5 due to the order of operations (PEMDAS/BODMAS), where division and multiplication are done before addition and subtraction. As a result, her formula is equivalent to:
=B2 + B3 + B4 + (B5 / 4)
This means that only the score in B5 is being divided by 4, and the other three scores (B2, B3, and B4) are added without being divided, which does not yield the correct average of the four quiz scores.
To correctly calculate the average of all four quiz scores, she should use parentheses to ensure that the sum of all four scores is calculated first, and then the result is divided by 4. The corrected formula should be:
=(B2 + B3 + B4 + B5) / 4
By using this formula, she will get the accurate average of her four quiz scores.