statistics/please check calculations
posted by mary on .
questions reads as follows:
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.
600500=100/100= 0.999999 would that be correct? if not how would you show the calculations?
*thank you very much.
mary hornbeck

Follow TutorCat's site to find
z=(xxmean)/standard deviation
to get
z=(600500)/100=1
http://mathworld.wolfram.com/zScore.html
The next step is to look up a probability table, or use your calculator to find out the onetail 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.