Class A has students with a mean test score of . Class B has students with a mean of . What is the mean score of all students?
Answer and explanation
Correct answer: C. 66
- Step 1: Total of class A: . Total of class B: .
- Step 2: Combined total: .
- Step 3: Mean .
Answer
66.
Why not the others: 65: This averages and , ignoring that class B has more students. 64: This gives the larger weight to class A, which has fewer students. 130: This adds the two means together.
Practise more Statistics and Probability.
Free questions with an explanation for every one, and full timed GCSE English and Maths Resits (Grade 4) mock tests.
More Statistics and Probability questions
- A café offers starters, main courses and desserts. How many different three-course meals are possible?
- A bag contains red, blue and green counters. One is taken at random. What is the probability it is not blue?
- The probabilities that a spinner lands on red, blue or green are , and . The spinner can only land on these three colours. Wh…
- Aisha's scores in four tests were . What score does she need in a fifth test to have a mean of exactly ?
- A fair coin is flipped and a fair six-sided die is rolled. What is the probability of getting a head and a ?
- A fair die is rolled twice. What is the probability of getting at least one six?