# Probability and normal distribution : key information

1. At a computer manufacturing company, the actual size of computer chips is normally distributed with a mean of 1 centimeter and a standard deviation of 0.1 centimeter. A random sample of 12 computer chips is taken. What is the standard error for the sample mean?

a) 0.029

b) 0.050

c) 0.091

d) 0.120

2. The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. If a sample of 25 fish yields a mean of 3.6 pounds, what is the Z-score for this observation?

a) 18.750

b) 2.500

c) 1.875

d) 0.750

3. The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. If a sample of 16 fish is taken, what would the standard error of the mean weight equal?

a) 0.003

b) 0.050

c) 0.200

d) 0.800

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#### Solution Summary

The solution solves the questions on probability and normal distributions.