# Suppose a batch of metal shafts produced in a manufacturing company have a standard deviation of 2.8 and a mean diameter of 210 inches.?

Suppose a batch of metal shafts produced in a manufacturing company have a standard deviation of 2.8 and a mean diameter of 210 inches.

If 84 shafts are sampled at random from the batch, what is the probability that the mean diameter of the sample shafts would be less than 209.7 inches? Round your answer to four decimal places.

### 1 Answer

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- stanschimLv 79 months ago
84 samples are sufficient to apply the normal distribution.

Z = (209.7 - 210) / 2.8 = -0.1071

P(Z < -0.1071) = 0.4574

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