Theoretical probability of heads = 50% (1/2) for a fair coin. Now let's see what actually happens.
Round 1 — 10 Flips. Tally each result below:
Heads (H):
Tails (T):
Total Heads: _____ Total Tails: _____ Check: Total = 10? ☐
My experimental probability of heads (10 flips): _____ ÷ 10 × 100 = _____%
Round 2 — 50 Flips. Flip in groups of 10. Tally each group:
| Group | Heads count | Tails count | Running heads total |
|---|---|---|---|
| Flips 1–10 | |||
| Flips 11–20 | |||
| Flips 21–30 | |||
| Flips 31–40 | |||
| Flips 41–50 | |||
| TOTAL (50 flips) |
My experimental probability of heads (50 flips): _____ ÷ 50 × 100 = _____%
Summary Comparison:
| Round | # Heads | Total Flips | Experimental % heads | Theoretical % heads | Difference from theoretical |
|---|---|---|---|---|---|
| 10 flips | 10 | 50% | |||
| 50 flips | 50 | 50% |
Draw a bar chart comparing your 10-flip %, your 50-flip %, and the theoretical 50%. Use different colors for each. Label the Y-axis in increments of 10% (0 to 100%).
Y-axis: Percentage of Heads (0–100%) | Color key: _____ = 10-flip _____ = 50-flip _____ = Theoretical
Draw your bars to the correct heights. Write the % value above each bar.
Which result was closer to the theoretical 50% — your 10-flip or 50-flip round? Use your actual percentages in your answer.
Explain the Law of Large Numbers using your own data as evidence.
Predict: If you flipped 200 times, approximately what % heads would you expect? Explain your reasoning.
1. A weather app says "70% chance of rain tomorrow." Does this mean it will definitely rain? Explain what it actually means.
2. A student flips a coin 5 times and gets tails every time. They say "heads is due next!" Are they right? Explain using what you know about probability.
3. A drug company says "our drug worked in 8 out of 10 patients in our trial." A different trial used 500 patients and found it worked in 400. Which result would you trust more, and why?
Find one example of probability being used in real life (news article, weather forecast, sports statistic, medical study, etc.).
What I found and what it means: