LESSON PLAN

Probability Experiments

Apothem Team

Grade 4 · Data & Probability

LESSON AT A GLANCE

Warm-up

5 min

Explore

15 min

Consolidate

10 min

Practice

12 min

Exit ticket

3 min

Warm-up

Bag with 4 red and 6 blue marbles. What is the theoretical probability of drawing red? (4/10 = 2/5.) Let us test: draw 20 times (replace each time). Record tallies. Calculate experimental probability. Compare to theoretical. Expect values near 2/5 but not exactly.

Explore

Probability experiment design: each group designs their own experiment (spinner, dice, or marble bag), predicts outcomes as fractions, runs 30 trials, records tallies, and calculates experimental probability fractions. Compare theoretical vs. experimental for each group.

Consolidate

Practice

Students run a 40-trial experiment, record with tallies, convert to fractions, and compare to theoretical probability. Play a hand game variant. Exit ticket: a bag has 5 red, 3 blue, 2 green. What is the theoretical probability of drawing green?

Exit ticket

TIP Emphasize: experimental and theoretical probabilities will rarely match exactly. That is the nature of chance. The larger the number of trials, the closer they will be. This is the most important concept in probability.

WORKED EXAMPLES

A spinner has 3 red sections, 2 blue sections, and 5 green sections. What is the theoretical probability of each colour?

Red: 3/10. Blue: 2/10 = 1/5. Green: 5/10 = 1/2. Total: 10/10 = 1. All outcomes together have probability 1 (certain).

In 40 trials, red appeared 14 times. What is the experimental probability? Compare to 3/10.

14/40 = 7/20 = 0.35. Theoretical: 3/10 = 0.30. Experimental is close but slightly above theoretical. Expected variation for 40 trials.

MATERIALS

•Fair coins, dice, spinners

•Coloured marble bags

•Tally recording sheets

•Probability fraction recording sheets

•Dene/Kaska hand game materials (if available)

WATCH FOR

!Students may expect experimental to match theoretical exactly. Emphasize: variation is normal and expected.

!Students may calculate theoretical probability without identifying all possible outcomes. Always list ALL outcomes first.