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Normal Distribution · Question 14 of 68

What Mathematics mark has a z-score of -1.5?

Question 14

EasyOriginal question

In a board's Mathematics exam the marks are normal with mean 60 and standard deviation 8; in its English exam they are normal with mean 55 and standard deviation 10. Aman scores 76 in Mathematics and 70 in English. (Take $P(0 < Z < 1) = 0.3413$ .)

What Mathematics mark has a $z$ -score of $-1.5$ ?

48

Correct answerYour answer

49

Correct answerYour answer

58

Correct answerYour answer

72

Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer A

Correct answer: A

$x = \mu + z\sigma$ .
$60 + (-1.5)(8) = 60 - 12 = 48$ .

Worth noting

72 adds the 12 marks; a negative $z$ lies below the mean.

Concept: A value from its z-score
Typical timeTypical: 90 s
Your timeYours: —

The rule this testsThe standard normal variate

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