Question 509790: this is the second one.
2.the test scores of students on a particular subject is normally distributed with a mean of 90. Jerry got a raw score of 95 in this test which is equivalent to the z-score of 2.50. What is the standard deviation of the test scores?
Lastly, i will not include the other questions:
3. on an examination, the mean was 78 and the standard deviation was 10. Find the standard score of a student who obtained 86 in the exam.
Thank you very much tutors, hope for the best answers. thank you for helping me.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! 2.the test scores of students on a particular subject is normally distributed with a mean of 90. Jerry got a raw score of 95 in this test which is equivalent to the z-score of 2.50. What is the standard deviation of the test scores?
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z = (x-u)/s
2.50 = (95-90)/s
s = 5/2.5
sigma = 2
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3. on an examination, the mean was 78 and the standard deviation was 10. Find the standard score of a student who obtained 86 in the exam.
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z = (x-u)/s
z = (86-78)/10 = 0.8
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Cheers,
Stan H.
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