Probability is all around us.
The results of all of these are determined by probability - also called chance.
In day to day life there are also many other places where the language of probability is also used.
A probability continuum is one way to visualise the scale of likelihoods.
Here is another visual explanation of the probability continuum.
An experiment or trial are the words used to describe the event or action of doing something and recording results. For example, the act of drawing cards from a deck, tossing a coin, rolling a dice, watching the weather, asking questions in a survey or counting cars in a carpark could all be examples of experiments or trials.
The sample space, sometimes called and event space, is a listing of all the possible outcomes that could arise from an experiment.
For example
Did you also notice how I listed the sample space? Using curly brackets { }.
An event is the word used to describe a single result of an experiment. It helps us to identify which of the sample space outcomes we might be interested in.
For example, these are all events.
We use the notation, P(event) to describe the probability of particular events.
Adding up how many times an event occurred during an experiment gives us the frequency of that event.
The relative frequency is the name given to the probability of that event happening.
Lets look at a situation and identify the experiment, sample space and event.
A standard die is rolled 10 times and the results are recorded. Particularly Tom was interested in even numbers.
EXPERIMENT - the experiment here is rolling a standard die
SAMPLE SPACE - the sample space for the experiment is {1,2,3,4,5,6}. That is we could get any of the numbers from 1 to 6 when I roll a standard die.
EVENT - the event Tom is interested in is the P(even number). The probability of getting an even number.
Two bags each have $1$1 blue ball and $2$2 yellow balls in them.
A ball is taken from one of the bags without looking. What is the probability that it is a yellow ball?
All the balls from both bags are put into one large new bag and mixed up. What is the probability of randomly picking a yellow ball from the new bag?
A fair die with the numbers $5$5, $6$6, $2$2, $4$4, $4$4 and $4$4 on it is rolled once. What is the probability of rolling a $3$3?
A game in a classroom uses this spinner.
What is the chance of spinning an odd number?
certain
even chance
impossible
likely
What is the chance of spinning a $2$2?
likely
impossible
certain
even chance
What is the chance of spinning a number less than $8$8?
likely
impossible
even chance
certain