Rachel scored 670 on the analytic portion of the GRE (Graduate Record Exam). GRE scores are normally distributed with a mean of 600 and a standard deviation of 30. How many standard deviations is Rachel's score above the mean?

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Answer:

Rachel's score is 2.3333 standard deviations above the mean

Step-by-step explanation:

GRE scores are normally distributed

Let be G the random variable ''Gre scores''

G  ~ N (mean,standard deviation)

G ~ N (600,30)

Rachel scored 670 on the analytic portion of the GRE.

670 - 600 will be the score above the mean

670 - 600 = 70

To find this in terms of standard deviation we divide by the standard deviation

70/standard deviation = 70/30 = 7/3 = 2.33333333 standard deviations