"Your lumber company has bought a machine that automatically cuts lumber. the seller of the machine claims that the machine cuts lumber to a mean length of 7 feet (84 inches) with a standard deviation of 0.4 inch. Assume the lengths are normally distributed. You randomly select 40 boards and find that the mean is 84.08

inches,

a. Assuming the seller's claim is correct, what is the probability that the mean of the sample is 84.06 inches or more?"

b. USING YOUR ANSWER FROM a what do you think of the sellers claims? does the seller's claim appear to be (accurate or inaccurate)?

c. The sample mean( should or should not) be considered unusual ?