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| Question 1119280:  .  Find the probabilities that a random variable will take on a value between 10 and 20 given that it has a normal distribution with:
 (a)  Mean  = 10 and s = 5
 
 
 
 
 
 (b)  Mean = 20  and s = 10
 
 Answer by Boreal(15235)
      (Show Source): 
You can put this solution on YOUR website! The z-score for any value=(x-mean)/sd For value between 10 and 20, the z score is between 0 and +2
 That is probability between 0.5000 and 0.9772, so the actual probability is the difference between the two or 0.4772
 For the second, this is the probability of z being between -1 or  (10-20)/10 and 0.  The second has probability of 0.5000 and the first 0.1587, and the difference is 0.3413, which represents the probability being between the values of 10 and 20.
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