Unveiling Measurement Uncertainty — Interactive Simulator

Area 3 MUST DO Option B  |  Accuracy, Precision & Error Analysis  |  SC.912.N.1.1 · N.1.4 · N.1.6

How to use: This simulation generates repeated measurements of a TRUE value of 10.000 g under two conditions. Click Roll 12 Trials (or press the spacebar) as many times as you like, and use the numbers to answer Parts 1–4 of the assignment. Re-rolling many times shows the key rule: averaging fixes RANDOM error but NOT SYSTEMATIC error.

Condition 1 — Systematic Only

Every reading = true + bias + scatter (readings cluster near true+bias).

TrialReading (g)Deviation (g)

Condition 2 — Random Only

Every reading = true + scatter (readings scatter evenly around 10.000).

TrialReading (g)Deviation (g)

What to watch for

1. Condition 1 (systematic): every reading is shifted up by the bias. Its mean stays near ~true+bias (~10.150) no matter how many times you roll — PRECISE but NOT accurate.
2. Condition 2 (random): readings scatter evenly around the true 10.000, so its mean lands very close to 10.000 — ACCURATE.
3. Averaging rule: roll many times. Condition 2’s mean hovers near 10.000; Condition 1’s mean stays ~0.15 g off. Averaging fixes random error, never systematic error.
4. Percent error for each condition is computed below (|mean − true| ÷ true × 100). Compare the two — which condition is more accurate?