Higher June 2017 Paper 2 Q12
12 There are 30 students in Mr Lear’s class.
16 of the students are boys.
Two students from the class are chosen at random.
Mr Lear draws this probability tree diagram for this information.
(a) Write down one thing that is wrong with the probabilities in the probability tree diagram. (1)
Owen and Wasim play for the school football team.
The probability that Owen will score a goal in the next match is 0.4
The probability that Wasim will score a goal in the next match is 0.25
Mr Slater says,
“The probability that both boys will score a goal in the next match is \(0.4 + 0.25\)”
(b) Is Mr Slater right?
Give a reason for your answer. (1)
Give a reason for your answer. (1)
| Answer | Mark | Notes |
|---|---|---|
| comment | C1 | for comment e.g. incorrect denominator for the 2nd student or probabilities for 2nd student do not add up to 1 |
| Answer | Mark | Notes |
|---|---|---|
| No (supported) | C1 | for “no” with supporting evidence, e.g. probabilities should be multiplied together or \(0.4 \times 0.25\) |