Calculate relative frequencies from given or collected data to estimate probabilities of events involving ‘and’ or ‘or’ (ACMSP226)

LO:To calculate relative frequency from given or collected data.


  • How to collect data
  • How to estimate probabilities of events


  • that calculating relative frequencies can help determine the probability of events occurring.


  • I can calculate relative frequency and estimate probability of events happening.

Relative Frequency

Relative frequency is how often something happens divided by all outcomes. Another way of thinking about it is frequency means how often something occurs. Relative means when compared to the total. So if you combine the two relative frequency could mean how often something occurs when compared to the total amount of outcomes.

It is usually written as a decimal value.

To find relative frequency you just divide the frequency of the item by the total number of outcomes.

The total of each item’s relative frequency should always have a sum of 1.

Relative Frequency Videos

“And” and “Or” Videos