Question 1197709: The reading test scores for the population of fifth graders is normally distributed with a mean of 55 and a standard deviation of 8.
What percentage of the fifth graders score less than 63?
Answer by Shin123(626)   (Show Source):
You can put this solution on YOUR website! By the empirical rule, 68% of fifth graders score within 1 standard deviation of the mean, or between 47 and 63. Since the normal distribution is symmetrical around the mean, 68/2=34% of fifth graders score between 55 and 63. Again, since the normal distribution is symmetrical, 50% of fifth graders score below the mean, so in total, 50+34=84% of fifth graders score less than 63.
If you need a more precise answer, we can use a z-table to get 84.134%.
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