Question 189591This question is from textbook saxon algebra 2
: A set of test scores is normally distributed with a mean of 82 and a standard deviation of 3. What percent of the scores are between 76 and 88?
I worked it out to: 82-76=6
88-82=6
6/3=2
What is the next step?
This question is from textbook saxon algebra 2
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! You're on the right track. What you've found is that the scores between 76 and 88 fall within 2 standard deviations of the mean. Since these scores are normally distributed (ie they fall on the bell curve), this means that 95% of the scores fall between 76 and 88
Note: 68% of scores fall within 1 standard deviation within the mean. Also, 95% of scores fall within 2 standard deviations within the mean. Finally, 99.7% of scores fall within 3 standard deviations within the mean (these are all approximations of course). This is called the 68-95-99.7 rule or the empirical rule. Unfortunately, this is something to be memorized (but it's very important in statistics)
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