Higher November 2024 Paper 5 Q11

OCRHigherCurrent spec6 marksBasic Probability

11 A bag only contains green, red, blue and yellow discs.

Orla carries out an experiment.
She picks one disc at a time from the bag, records its colour and then returns the disc to the bag.
When she has finished the experiment, Orla works out the relative frequency of each colour.
Some of her results are shown in the table.

ColourGreenRed
Relative frequency0.350.25

The relative frequency of the yellow discs was three times the relative frequency of the blue discs.

In total, there are 2000 discs in the bag.

(a) Use this information to find an estimate for the total number of green and yellow discs that are in the bag.
You must show your working. [5]
(b) Explain why your estimate may not be reliable. [1]