E09 Review Scores on "The ability to do quantitative thinking" test are normally distributed with a mean of 250 and a standard deviation of
25. Brandi scored at the 81st percentile on this test. What was her test score?
is the test score for Brandi.

272 is the test score for Brandi.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean and standard deviation , the z-score of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Mean of 250 and standard deviation of 25:

This means that

Brandi scored at the 81st percentile on this test. What was her test score?

The z-score of her score of X has a p-value of 0.81. This means that her score is given by X when Z = 0.88.

272 is the test score for Brandi.

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step-by-step explanation: