Compare observed frequencies across experiments with expected frequencies (ACMSP146)

LO:To compare observed frequencies with expected frequencies.


    • How to calculate observed frequencies

How to calculate expected frequencies


  • That observed frequencies can produce different results from expected frequencies.


  • I compare observed frequencies with expected frequencies.

Observed Frequency

Observed frequency is the actual results of what did you see or observe.

Sometimes observed frequency does not equal what you expect it to be.

Expected Frequency

Expected frequency is what should the results look like based on probability scales.

For example, if I had a fair coin and I tossed it 100 times, I should expect it to land heads 50% of the time and tails the other 50% of the time.

Observed Frequencies do not have to always match expected frequencies!!!

Frequency Tables

A frequency table can be used to help record how often a result occurs.

You can also group data in a grouped frequency table. It helps to organise grouped data in a table.

For example, 25 would be in the 20-30 row and 72 would fall into the 70-80 row.

Teaching Ideas

ACARA Work Samples

Observed vs. Expected Frequency Videos