Question 1089149: hello , can anyone please help me on these question of normaly distribution question ? i dont understand the question
the thickness of the gear blanks produced by an automatic lathe is known to be normally distributed, with a mean of 0.05in. and a standard deviation of 0.05in.
if 10% of the blank are rejected for being too thin, find the value of the lower specification.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! the thickness of the gear blanks produced by an automatic lathe is known to be normally distributed, with a mean of 0.05in. and a standard deviation of 0.05in.
If 10% of the blanks are rejected for being too thin, find the value of the lower specification.
Draw a normal curve; put the mean 0.05" in the middle
Mark a left-tail with 10% of the area under the curve.
You want the value that determines that 10% area.
-----
Corresponding to that figure you have a normal curve for z-values.
Find the z-value that determines a left-tail of 10%.
invnorm(0.10) = -1.2816
----
Find the corresponding thickness value::
x = z*s+u
x = -1.2816*0.05+0.05
Note:: That would be a negative value.
You probably posted the wrong standard deviatioin value.
----
Cheers,
Stan H.
-----------
|
|
|
