Vocabulary

Statistics - the study of collecting, organizing and interpreting data.

Population - a group of items or individuals from which a sample is taken.

Survey - a question or set of questions used to collect data.

Sample - a randomly selected group, used for collecting data.

Concepts

The probability of an event occurring is found by dividing the number of the desired sample by the total population in the event.

P(a) = $\frac{\mathrm{Desired\; Outcome}}{\mathrm{Total\; Population}}$

Rules

1. Calculate the total number in the population.
2. Find the total number in the desired outcome.
3. Divide the desired outcome by the total population.
4. Write in the form requested (simplified fraction, decimal or percent).

Example

The table shows how students traveled to school one morning. What is the probability that a student rode their bike to school? 

$\frac{5}{32}$

$\frac{7}{32}$

$\frac{1}{4}$

$\frac{3}{8}$

Solution

Out of a total of 32 students, 12 rode their bikes to school. That is a probability of $\frac{12}{32}$ = $\frac{3}{8}$.

Pre-requisite Skills

Write Probability as Percentage, Fraction and Decimals (6.9.1)