In standardized scores of achievement motivation that are normally distributed, the US group has a mean score of 35 with a standard deviation of 14. Higher scores correspond to more achievement motivation. Shamu scored in the top 20% of the test takers. What was her score?

Question

Mathematics

Ethan Turner

8 May, 23:41

In standardized scores of achievement motivation that are normally distributed, the US group has a mean score of 35 with a standard deviation of 14. Higher scores correspond to more achievement motivation. Shamu scored in the top 20% of the test takers. What was her score?

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Answers (1)

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Andreas Leblanc · Answer 1

x = 46.033

Step-by-step explanation:

mean score (μ) = 35

standard deviation = 14

shamu scored 20% i. e (0.2) of the test

so

we will take value from the z-table at 0.80 from the left of it.

so z-value comes out to be =.78814

using standard formula

x = μ + z * σ

x = 35 + 0.78814 * 14

x = 46.033