A psychologist has designed a questionnaire to measure individuals' aggressiveness. suppose that the scores on the questionnaire are normally distributed with a standard deviation of . suppose also that exactly of the scores exceed . find the mean of the distribution of scores. carry your intermediate computations to at least four decimal places. round your answer to at least one decimal place.

        μ = 647.4

Step-by-step explanation:

The question says

"A psychologist has designed a questionnaire to measure individuals' aggressiveness. suppose that the scores on the questionnaire are normally distributed with a standard deviation of . suppose also that exactly of the scores exceed"

And we are told to find the mean of the distribution scores.

Given mean μ = ?

we have from standard normal table that

P(Z > 1.282) = 0.1

Therefore the given Z score of a score of 750 is given thus 1.282.

the z score is given:

x - μ / α = 1.282

750 - μ / 80 = 1.282

Therefore μ = (750 - 80)*1.282 = 647.4

So we have that μ = 647.4

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