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probability

Probability vocabulary

Explain chance, outcome, event, likely, unlikely, fair, random and experiment.

Quick answer

Probability vocabulary helps us talk about how likely something is to happen. Words like chance, outcome, event, likely, unlikely, fair, random and experiment help us understand and describe what might happen in games, weather, or everyday life.

Learning outcome

By the end of this page, you will be able to use probability words to describe how likely different things are to happen in games, real life, and experiments. Success signs:
  • You can say whether something is likely, unlikely, or certain to happen
  • You can explain what an outcome is in a game or experiment
  • You can tell the difference between fair and unfair games
  • You can describe what a random event means

Why this matters

Probability vocabulary helps us understand the world around us. When we play games, we use words like "likely" and "unlikely" to decide what to do. When we talk about weather, we say "it's likely to rain" or "it's unlikely to snow in summer." Understanding these words helps us make good choices and predict what might happen next. In school, probability vocabulary helps us work with chance, data, and statistics. When you grow up, you'll use probability words when you talk about risk, weather forecasts, or even planning your future.

How it works

Probability words help us describe how likely something is to happen. Let's look at each word one by one: Chance – This is how likely something is to happen. If you roll a dice, there's a chance you'll get a 6. Outcome – This is what happens when you do something. If you flip a coin, the outcomes are heads or tails. Event – This is a specific thing that might happen. For example, "rolling a 3 on a dice" is an event. Likely – This means something will probably happen. If you go outside in winter, it's likely to be cold. Unlikely – This means something will probably not happen. If you roll a dice, it's unlikely to get a 7. Fair – A fair game or situation gives everyone the same chance. If you and your friend are sharing a pizza, it's fair if you both get the same amount. Random – This means things happen without a pattern or order. If you pick a name from a hat, it's random which name you get. Experiment – This is when you do a test or try something to see what happens. Like testing if a plant grows better in sun or shade.

Examples you can see

Let's look at some examples to understand better: Example 1: Coin Flip You flip a coin. What are the outcomes?
  • Heads
  • Tails
These are the two possible outcomes. Each has an equal chance of happening, so the event of getting heads is likely, and the event of getting tails is also likely. Example 2: Dice Roll You roll a six-sided dice.
  • What is the chance of rolling a 1?
  • What is the chance of rolling a number between 1 and 6?
  • What is the chance of rolling a 7?
The chance of rolling a 1 is 1 in 6, which means it's unlikely to happen. The chance of rolling a number between 1 and 6 is 6 in 6, which means it's certain to happen. The chance of rolling a 7 is 0 in 6, which means it's impossible. Example 3: Fair or Unfair? You have a bag with 3 red marbles and 1 blue marble.
  • If you pick a marble at random, what is the chance of getting red?
  • Is this a fair game?
The chance of getting red is 3 in 4. The chance of getting blue is 1 in 4. This is not fair because you're more likely to get red than blue.

Try it as a mini adventure

Adventure: The Magic Dice Game You are a wizard who has a special dice with 6 faces. Each face has a different magic spell. You roll the dice to see which spell you cast. You're going to play this game 10 times. Round 1: You roll the dice and get a spell that makes a flower grow.
  • What is the outcome?
  • Is this likely or unlikely?
Round 2: You roll the dice and get a spell that makes a bird fly.
  • What is the outcome?
  • Is this likely or unlikely?
Round 3: You roll the dice and get a spell that makes a fireball appear.
  • What is the outcome?
  • Is this likely or unlikely?
Round 4: You roll the dice and get a spell that makes a rainbow appear.
  • What is the outcome?
  • Is this likely or unlikely?
Round 5: You roll the dice and get a spell that makes a dragon appear.
  • What is the outcome?
  • Is this likely or unlikely?
Round 6: You roll the dice and get a spell that makes a rainbow appear.
  • What is the outcome?
  • Is this likely or unlikely?
Round 7: You roll the dice and get a spell that makes a fireball appear.
  • What is the outcome?
  • Is this likely or unlikely?
Round 8: You roll the dice and get a spell that makes a flower grow.
  • What is the outcome?
  • Is this likely or unlikely?
Round 9: You roll the dice and get a spell that makes a bird fly.
  • What is the outcome?
  • Is this likely or unlikely?
Round 10: You roll the dice and get a spell that makes a dragon appear.
  • What is the outcome?
  • Is this likely or unlikely?
After 10 rounds, you notice that some spells happen more often than others. You can say which spells are more likely to happen based on how often they appear.

Common mistakes

  • Mistake: Thinking that if something happens once, it will happen again. Why it happens: Children sometimes think that if they roll a 6 once, they must roll a 6 again soon. Fix: Explain that each roll is separate and independent. Rolling a 6 doesn't make it more likely to roll a 6 again.
  • Mistake: Confusing likely and certain. Why it happens: A child might say "it's likely to rain tomorrow" when they mean "it's certain to rain." Fix: Help them understand that certain means it will definitely happen, while likely means it will probably happen.
  • Mistake: Thinking that all outcomes are equally likely. Why it happens: A child might think that when rolling a dice, each number has the same chance of appearing. Fix: Show that with a fair dice, each number has the same chance, but with unfair dice, some numbers might be more likely.
  • Mistake: Mixing up fair and random. Why it happens: A child might say a game is fair if the results are random. Fix: Explain that fair means everyone has an equal chance, while random means no pattern.

Parent and carer guide

As a parent or carer, you can help your child understand probability vocabulary in many fun ways:
  • Play games: Play board games, card games, or dice games and talk about what might happen next.
  • Use everyday examples: Talk about weather, sports, or daily events using probability words.
  • Ask questions: Ask your child "What do you think will happen?" or "Is that likely or unlikely?"
  • Make predictions: Have your child predict what will happen in a story or experiment.
  • Use visual aids: Draw pictures or use objects to show outcomes and chances.
Remember, don't worry if your child gets confused at first. Probability vocabulary takes time to understand. Be patient and keep playing with the words and ideas.

Practice questions

  1. What is the outcome when you flip a coin?
  2. Is it likely or unlikely to roll a 6 on a dice?
  3. What makes a game fair?
  4. Is it random if you always get the same result?
  5. What is the chance of getting a head when flipping a coin?
Answers:
  1. Heads or tails
  2. Unlikely
  3. Everyone has the same chance
  4. No, it's not random
  5. 1 in 2 or 50%

FAQ

What does "outcome" mean in probability?

An outcome is what happens when you do something. For example, when you flip a coin, the outcomes are heads or tails.

What is the difference between "likely" and "certain"?

Likely means something will probably happen, but it's not guaranteed. Certain means it will definitely happen.

Can a game be fair but not random?

Yes! A game can be fair, meaning everyone has an equal chance, but the results might follow a pattern. Random means no pattern, but not necessarily fair.

What is an experiment in probability?

An experiment is when you do a test or try something to see what happens. For example, flipping a coin 10 times to see how many times it lands on heads.

How can I help my child learn probability words?

Play games, use real-life examples, ask questions, and talk about chance and likelihood in daily activities. Use visual aids and make it fun!