Explanation 1
Each value contributes according to its weight.
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Lesson 11 of 15
Calculate weighted averages after validating whether weights represent shares, frequencies, or importance.
Theory
Calculate weighted averages after validating whether weights represent shares, frequencies, or importance. The examples in this lesson use fictional STATLAB Academy business data and independently written explanations.
Explanation 1
Each value contributes according to its weight.
Explanation 2
Weights may be normalized when appropriate.
Explanation 3
Weighted and simple means answer different questions.
Notation and formulas
x-bar_w = sum(w_i x_i) / sum(w_i)
Calculate weighted averages after validating whether weights represent shares, frequencies, or importance.
Interactive Mission
| Category | Value | Weight % | Contribution |
|---|---|---|---|
| Quiz | 16.40 | ||
| Assignment | 26.40 | ||
| Project | 45.50 |
Weight total
100.0%
Valid total
Weighted mean
88.30
Simple mean
87.00
R connection
Run and edit the code, inspect printed output, and use the movable R Code Guide for line-by-line help.
Live R Lab
Validate weights and estimate mean and standard deviation from grouped frequencies.
Ready to run
Worked example
Scenario
A fictional training organization needs to use weighted means to support an operational decision.
The best summary is the one that fits the question, data structure, units, and distribution.
Interpretation safeguard
Do not assume percentages sum correctly; validate or normalize with a clear explanation.
Dataset provenance
Original synthetic data generated for STATLAB Academy. No textbook data used.
Reflection
Name the question, data structure, units, chosen method, and one limitation.
Assistant
Coach me through Weighted Means without giving direct quiz answers or writing my final report. Ask me to justify assumptions, units, and interpretation.
Exit check
Use a hint before checking if needed. Explanations appear only after an answer is submitted.
Checkpoint
Question 1 of 2. Answered 0/2. Passing score: 70%.