sweety8enmjessicass
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Could someone PLEASE help?
The mean of the scores obtained by a class of students on a physics test is 42. The standard deviation is 8%. Students have to score at least 50 to pass the test.
Assuming that the data is normally distributed, ?% of the students passed the test.
I'm not sure if I'm understanding the question correctly. The deviation 8% means what?

Answer :

nobillionaireNobley
Let X be a random variable representing the score of of student.
P(X ≥ 50) = 1 - P(X < 50) = 1 - P(z < (50 - 42)/8) = 1 - P(z < 1) = 1 - 0.84134 = 0.15866

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