Question 281358: A.The diameters of bolts produced by a certain machine are normally distributed with a mean of U=0.30 inches and a standard deviation, r=0.042, inches. What percentage of bolts will have a diameter greater than 0.320 inches?
B.If 11 bolts are selected, what percentage of bolts will have a mean diameter greater than 0.32 inches?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A.The diameters of bolts produced by a certain machine are normally distributed with a mean of U=0.30 inches and a standard deviation, r=0.042, inches. What percentage of bolts will have a diameter greater than 0.320 inches?
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z(0.320) = (0.320-0.300)/0.42 = 0.0476
P(x > 0.32) = P(z > 0.0476) = 0.4812 = 42.12%
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B.If 11 bolts are selected, what percentage of bolts will have a mean diameter greater than 0.32 inches?
z(0.32) = (-.320-0.300)/[0.42/sqrt(11)] = 0.1579
P(xbar > 0.32) = P(z > 0.1579) = 0.4373 = 43.73%
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Cheers,
Stan H.
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