Neha scored 68 in Physics, where the marks have mean 60 and standard deviation 5, and 75 in Chemistry, where they have mean 65 and standard deviation 8. In which subject did she do better compared with the others?

Chemistry, since 75 is more than 68Correct answerYour answerChemistry, since it is 10 marks above the mean against 8Correct answerYour answerEqually well in bothCorrect answerYour answerPhysics, since

z = 1.6

against

z = 1.25

Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer D

Correct answer: D

Physics: $z = \frac{68 - 60}{5} = 1.6$ . Chemistry: $z = \frac{75 - 65}{8} = 1.25$ .
The higher $z$ is the better relative score: Physics.

Worth noting

10 marks above the mean is less impressive when the marks are spread wider, with standard deviation 8.

Concept: Comparing scores with z
Typical timeTypical: 90 s
Your timeYours: —

The rule this testsThe standard normal variate

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Ten questions from Normal Distribution, at your own pace.

Neha scored 68 in Physics, where the marks have mean 60 and standard deviation 5, and 75 in Chemistry, where they have mean 65 and standard deviation 8. In which subject did she do better compared with the others?

Explanation