Free Printable Frequency trees PDF Worksheets, Revision Guide & GCSE Past Paper Questions (Grade 3)
Download free frequency trees worksheets (PDF), GCSE maths past paper questions and worked solutions for Frequency trees (3Y). This is a Grade 3 probability topic from the GCSE questions by topic collection for Foundation and Higher tier GCSE Maths (Edexcel, AQA, OCR and IGCSE).
A frequency tree organises data by splitting a total group into two categories, and then splitting each branch further. The two branches coming out of any circle must always add up to the number inside that circle.
Work through the clues step by step, filling in any numbers given directly and subtracting from the parent circle to find the partner branch. When asked for a probability at the end, check carefully whether it is out of the whole group or a specific subgroup.
Example 1:60 students sat a test. 35 are girls. 28 girls passed. In total, 47 students passed. Complete the frequency tree.
Boys = 60 − 35 = 25; Girls Fail = 35 − 28 = 7
Boys Pass = 47 − 28 = 19; Boys Fail = 25 − 19 = 6
Example 2: Using the frequency tree from Example 1:
(a) One student is chosen at random. Find P(Boy who failed).
(b) A boy is chosen at random. Find P(Passed).
Solution:
(a) Out of all 60 students, 6 are boys who failed:
P(Boy who failed) = 660 = 110
(b) Out of the 25 boys, 19 passed:
Answer: (a) 660 (or 110) (b) 1925
Scanned GCSE Exam Questions & Worked Solutions
GCSE Past Paper Frequency trees Questions & Answers
A travel agent sold 100 holidays in April. Each of these holidays was in the UK or was abroad. 64 of the 100 holidays were sold to families. The rest of the holidays were sold to couples. 11 of the 18 holidays abroad were sold to couples.
(a)Use this information to complete the frequency tree.[3 marks]
(b)Find the probability that this holiday was **not** abroad.[2 marks]
Some students were asked about their daily exercise.
(a)12 more students answered Yes than answered No. Complete the frequency tree.[3 marks]
(b)One of the 35 students who answered Yes is chosen at random. What is the probability that they exercise for at least 1 hour?[1 mark]
Worked Solution & Mark Scheme (4 marks)
Part (a) Solution:
Yes = 35 M1 Since Yes is 12 more than No: No = 35 - 12 = 23 M1 Total students = 35 + 23 = 58 From 35 Yes students, 27 exercise at least 1 hour, so 35 - 27 = 8 exercise less than 1 hour. A1
Answer (a): Answer Total = 58, No = 23, Less than 1 hour = 8
Part (b) Solution:
Out of the 35 students who answered Yes, 27 exercise for at least 1 hour, so probability = 2735. B1
120 people were at a hockey match. Each person was asked if they wanted to stand or to sit to watch the match. [INDENT]75 of the people were female [INDENT]29 of the males wanted to stand [INDENT]30 of the people wanted to sit
(a)Use this information to complete the frequency tree.[3 marks]
(b)Write down the probability that this person is a male who wanted to stand.[1 mark]
Worked Solution & Mark Scheme (4 marks)
Part (a) Solution:
Males = 120 – 75 = 45 M1 Male sit = 45 – 29 = 16 M1 Female sit = 30 – 16 = 14 Female stand = 75 – 14 = 61 A1