IntroStatsCalc

Weighted Mean and GPA

Weighted averages such as GPAs and course grades.

Inputs

For a GPA, the grade points (A = 4, B = 3, …). For a course grade, each category's score.

Credits, or percentages such as 20 15 45 20. Same order as the values.

Results update as you type.

Results

Weighted mean = 3.0833

Counting each value according to its weight, the average is 3.0833.

Each value times its weight
Value xWeight ww · x
4416
339
248
414
Total1237

On the TI-84

Put the values in L1 and the weights in L2. STAT → CALC → 1:1-Var Stats with FreqList L2 (works when the weights are whole numbers), or compute sum(L1*L2)/sum(L2) on the home screen (sum is under 2nd STAT → MATH).

sum(L1*L2)/sum(L2)

Show steps
  1. Formula. x̄ = Σ(w · x) ÷ Σw
  2. Multiply and add. Σ(w · x) = 4(4) + 3(3) + 4(2) + 1(4) = 37
  3. Divide by the total weight. 37 ÷ 12 = 3.0833

About this calculator

When values don't count equally

A regular mean treats every value the same. A weighted mean lets some values count more. In a GPA, a 4-credit course counts four times as much as a 1-credit lab. In a course grade, a final worth 20% counts more than homework worth 10%.

How it works

Multiply each value by its weight, add those products, and divide by the total of the weights. If the weights are percentages that add to 100, dividing by 100 gives the course grade.

More descriptive calculators: Random Sample · Frequency Table & Histogram · 1-Var Stats · Boxplot & Outliers · Z-Scores · Percentiles · Empirical Rule & Chebyshev