Probability and Data — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Flipping two fair coins, the chance of getting two heads is 1 in 4.
Two coins have four equal outcomes and only HH is two heads, so the probability is one in four.
2. A spinner has 4 equal sectors. The chance of landing on red is 1 out of 4.
Equal sectors give equal chances, and one red sector out of four total gives a one in four chance.
3. Out of 20 spins, red came up 5 times. The experimental probability is 5 out of 20.
Experimental probability uses observed counts, so five reds in twenty spins yield five out of twenty.
4. If the chance of rain is 1 in 5, then in 25 days you expect rain on about 5 days.
Twenty-five days times one fifth gives five expected rainy days as a reasonable prediction.
5. Flipping two coins, the chance of getting one head and one tail is 2 out of 4.
Two outcomes (HT and TH) out of four equal possibilities give a two in four chance overall.
6. A spinner with sectors red, blue, green, yellow lands on green with chance 1 out of 4.
Equal sectors give equal probability, and one green sector out of four equals a one in four chance.
7. If a die shows 4 in 6 of 30 rolls, the experimental probability is 6 out of 30.
Experimental probability uses actual outcomes, so six fours out of thirty rolls equals six out of thirty.
8. Two coins flipped 40 times, expect about 10 flips of two heads.
Forty flips times one fourth equals ten expected double heads, a fair prediction from theory.
9. A 4-sector spinner spun 16 times should land on blue about 4 times.
Sixteen times one fourth equals four expected blue spins as a reasonable prediction.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Two-coin flip outcomes
→ HH, HT, TH, TT total four
HH, HT, TH, TT total four
Four-sector spinner
→ Each color has 1 in 4 chance
Each color has 1 in 4 chance
Experimental probability
→ Based on observed data counts
Based on observed data counts
Predicted outcomes
→ Multiply chance by total trials
Multiply chance by total trials
Pairing terms with definitions reinforces probability vocabulary and helps students apply rules to new compound events.