Question 571889: A set of data is normally distributed with a mean of 100 and standard deviation of 15.
· What would be the standard score for a score of 85?
· What percentage of scores is between 100 and 85?
· What would be the percentile rank for a score of 85?
I am lost and my teacher will not respond to me via email or anything. PLEASE HELP!!!
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A set of data is normally distributed with a mean of 100 and standard deviation of 15.
· What would be the standard score for a score of 85?
z(85) = (85-100)/15 = -15/15 = -1
That means 85 is one standard deviation to the left of the mean.
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· What percentage of scores is between 100 and 85?
One standard deviation from the mean covers 34% of the population.
normalcdf(85,100,100,15) = 0.3413
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· What would be the percentile rank for a score of 85?
The tail to the left of 85 must have 0.5000-0.3413 = 0.1587 of the population.
The percentile score must be 15.87%ile
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Cheers,
Stan H.
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