Question 581451: This are questions from homework from the other week. My professor already gave me the answers but not how to do the work; it is an online statistics class. I have been looking up things. I want to make sure how to do the steps properly. Below are the questions. Thank you so much!
Given a test that is normally distributed with a mean of 30 and a standard deviation of 6, what is the probability that a single score drawn at random will be greater than 34?
If scores are normally distributed with a mean of 85 and a standard deviation of 10, approximately what percentage of the scores are between 60 and 100?
If scores are normally distributed with a mean of 85, and a standard deviation of 10, approximately what percentage of the scores are greater than 80?
If scores are normally distributed with a mean of 85, and a standard deviation of 10, approximately what percentage of the scores are greater than 95?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Given a test that is normally distributed with a mean of 30 and a standard deviation of 6, what is the probability that a single score drawn at random will be greater than 34?
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z(34) = (34-10)/6 = 4/6 = 2/3
P(x > 34) = P(z > 2/3) = normalcdf(2/3,100) = 0.2525
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If scores are normally distributed with a mean of 85 and a standard deviation of 10, approximately what percentage of the scores are between 60 and 100?
z(60) = (60-85)/10 = -25/10 = -2.5
z(100) = (100-85)/10 = 15/10 = 3/2
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P(60 < x < 100) = P(-2.5 < z < 3/2) = normalcdf(-2.5,3/2) = 0.9270
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Use the same procedure for the last 2 problems.
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Cheers,
Stan H.
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If scores are normally distributed with a mean of 85, and a standard deviation of 10, approximately what percentage of the scores are greater than 80?
If scores are normally distributed with a mean of 85, and a standard deviation of 10, approximately what percentage of the scores are greater than 95?
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