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May 6, 2016

# Homework Help: statistics/please check calculations

Posted by mary on Saturday, October 16, 2010 at 2:31pm.

sat scores around the nation tends to have a mean score around 500, a standard deviation of 100 points and are approximately normal distribution. a person who scores 600 on the sat has approximately what percentile rank within the population? please show all calculatons.

600-500=-100/100= 0.999999 would that be correct? if not how would you show the calculations?

*thank you very much.
mary hornbeck
• statistics/please check calculations - MathMate, Saturday, October 16, 2010 at 3:40pm

z=(x-xmean)/standard deviation
to get
z=(600-500)/100=1

http://mathworld.wolfram.com/z-Score.html

The next step is to look up a probability table, or use your calculator to find out the one-tail probability (i.e. every score lower than 600). For a probability table, try:

http://www.math.unb.ca/~knight/utility/NormTble.htm

to find that for z=1.0, the probability is 84.13%.

Notice that for z=0 (exactly in the middle of the normal curve, or the mean =500, the probability is 0.5.