[Rows in a table are labelled "Type of fish" and "Number of fish". The table reads "Murray Cod - 45, Callop - 15, Catfish - 60 and Perch - 45". The narrator reads out the onscreen text.]

NARRATOR: Question three. A section of the Murray River had a sample of 165 fish taken from it. The results are shown in the table below. Part a. What is the relative frequency of obtaining Murray Cod or Callop? Part b. What is the relative frequency of obtaining Perch or Callop or Catfish?

Part a. What is the relative frequency of obtaining Murray Cod or Callop? There are 45 Murray Cod and 15 Callop. This gives a total of 45 plus 15, so 60 Murray Cod or Callop. There is a total of 165 fish altogether. This gives a relative frequency of 60 out of a possible 165 fish, which simplifies to four-elevenths.

Part b. What is the relative frequency of obtaining Perch or Callop or Catfish? There are 45 Perch, 15 Callop and 60 Catfish. There is a total of 45 plus 15 plus 60, which gives 120 fish that can be classed as Perch or Callop or Catfish. There is a total of 165 fish altogether. This gives a relative frequency of 120 out of 165, which simplifies to eight-elevenths.