Question 1102984: A distribution ofmeasurements is relatively mound-shaped with mean 90 and standard deviation 10.
(A) what proportion of the measurements will fall between 80 and 100?
(B) what proportion of the measurements will fall between 70 and 100?
(C) what proportion of the measurements will fall between 30 and 60?
(D) if a measurement ischosen at random from this distribution, what is the probability that it will be greater than 100?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! Assuming normal distribution.
a. is a z between -1 and 1, since z=(x-mean)/sd
That is probability of 0.6827.
b. between 70 and 100 is between z of -2, and 1, which is 0.8186
c. Between 30 and 60 is a z of -6 and -3, which is probability of 0.0013
d. Greater than 100 is a z>+1, which is 0.1587.
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