Foundation November 2019 Paper 2 Q20
20 A bag contains 100 pencils that are either red or green.
Describe a method you could use to estimate the number of red pencils in the bag without looking into the bag or having more than one of the pencils out of the bag at any one time. [4]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| Select a pencil from the bag and record results and put it back in the bag oe | 1 | Steps may be combined together | |
| Repeat trial at least 10 times | 1 | Accept many, a lot etc clearly implied | |
| Find rel frequency or prob | 1 | eg \(\dfrac{\text{no of red pencils}}{\text{no of trials}}\) oe or no of red pencils recorded and no of trials recorded or number of greens recorded oe | oe eg if number of trials = 20 and then number of reds × 5 or no of red pencils × \(\dfrac{100}{\text{no of trials}}\) oe then allow both marks |
| Rel freq × 100 oe | 1 | ||