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# weights of catfish are normally distributed

1. 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. What percentage of samples of 4 fish will have sample means between 3.0 and 4.0 pounds?
a) 84%
b) 67%
c) 29%
d) 16%

2. The standard error of the mean for a sample of 100 is 30. In order to cut the standard error of the mean to 15, we would
a) increase the sample size to 200.
b) increase the sample size to 400.
c) decrease the sample size to 50.
d) decrease the sample to 25.

3. The amount of time required for an oil and filter change on an automobile is normally distributed with a mean of 45 minutes and a standard deviation of 10 minutes. A random sample of 16 cars is selected. What would you expect the standard error of the mean to be?
a) 0.625 minutes
b) 3.2 minutes
c) 2.5 minutes
d) 4.5 minutes

#### Solution Preview

1. 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. What percentage of samples of 4 fish will have sample means between 3.0 and 4.0 pounds?
a) 84%
b) 67%
c) 29%
d) 16%

Mean = 3.2 pounds

Std Dev of Population = 0.8 pound

Std dev ...

#### Solution Summary

The solution calculates probability that the sample mean lies between certain values.

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