Question:The hardness of a metal is determined by forcing a hardened
point into the surface and...
Question
The hardness of a metal is determined by forcing a hardened
point into the surface and...
The hardness of a metal is determined by forcing a hardened
point into the surface and then measuring the depth of penetration
of the point. Suppose the hardness of a particular metal is
normally distributed with mean 70 and standard deviation 3.
If a sample is acceptable only if its hardness is between 67
and 75, what is the probability that a randomly chosen sample has
an acceptable hardness? (12 pts)
If the acceptable range of hardness is (70-c, 70+c), for what
value of c would 95% of all specimens have acceptable hardness?
(13 pts)