Statistics Didn’t Have to Be This Hard · Chapter 2

Weighted Average

When the parts don’t count equally, a plain average misleads. Enter each score and how much it counts, and see the weighted average, plus what you need on the last part to reach a target.

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Enter the scores and weights, then press Calculate.
From the book, Chapter 2. Ben’s grade: homework 92 (20%), midterm 74 (30%), final 81 (50%) gives 18.4 + 22.2 + 40.5 = 81.1, not the plain average 82.3. To finish on 85 he’d have needed 88.8 on the final. Weights that don’t add to 100% are scaled so they do.

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