Question 1180818: 2) If the readings on thermometers are normally distributed with a mean of 0o C and a standard deviation of 1.00o C.
a) If 5 % of thermometers are rejected because they have readings that are too low, but the rest are accepted, what is the reading that separates the rejected thermometers from the others.
b) What is the 90th percentile?
c) If 3 % of thermometers are rejected because they have readings that are too high and 4 % are rejected because they are too low, what are the cutoff values separating the rejected thermometers from the others?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! a. z(0.05)=-1.645, so temp is -1.645 C.
b. 90th percentile is +1.282 C.
z(0.04)=-1.75 C. and z(0.97)=+1.88 C.
Those are the lower and upper limits respectively.
use 2nd VARS3invnorm(0.05,0,1)ENTER, where 0.05 would be the 5th percentile, the 0, 1 are mean and sd of the standard normal distribution.
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