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On a test that has a normal distribution, a score of 30 falls three standard deviations below the mean, and a score of 60 falls three standard deviations above the mean. Determine the mean of this test.

Answer :

MHANIFAGO

Answer:

  • 45

Step-by-step explanation:

Let μ - mean, σ - standard deviation.

Given:

A score of 30 falls three standard deviations below the mean:

  • μ - 3σ = 30

A score of 60 falls three standard deviations above the mean:

  • μ + 3σ = 60

Add up the two expressions and find the value of μ:

  • μ - 3σ + μ + 3σ = 30 + 60
  • 2μ = 90
  • μ = 45

The mean is 45

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