Question 1059035: 4. Give a normally distributed population with a mean of 75 and a variance of 625. Find the following probability
a. P (x<60);
b. P(x≥85).
c. P(43≤x≤110)
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! z=(x-mean)/sd
=(60-75)/25, since sd is the square root of the variance, and the variance is 625.
=-15/25.
want p z<-0.6, and that is 0.2743
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want p > 10/25 by the same reasoning.
That is probability z>0.4, which is 0.3446
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Want z between two values
(43-75)/25 and (110-75)/25
That is between -1.28 and +1.4, or 0.8190.
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