= 22pt

Math 3310 --- Practice Problems
August 28, 2000

1. The monthly advertising expenditure of Discount Hardware is normally distributed with a s = $100. We take a random sample of 10 months and find a sample mean of $380.00. Find a 90% Confidence Interval for µ.

2. The manager of a gift shop would like to estimate the average retail price of a particular greeting card by its competitors. A random sample of 20 stores were selected, with a mean of $2.05 and a standard deviation of $0.40. Find a 99% Confidence Interval for µ.

3. An apartment finder service would like to estimate the average cost of a one bedroom apartment in Kansas City. A random sample of 41 apartment complexes yields a mean of %310.57 and a standard deviation of $29. Find a 90% Confidence Interval for µ.

4. An economist surveyed 48 heating oil dealers and obtained a sample mean cost of 97.8 cents, and a sample standard deviation of 3.1 cents. Find a 95% Confidence Interval for µ.

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