The amounts of insurance claims that a car dealership submits each year are normally distributed with a population standard deviation of 3.5 claims and an unknown population mean. A random sample of 30 dealerships is taken and results in a sample mean of 39 claims. Find the margin of error for a 90% confidence interval for the population mean.
Z0.10 Z0.05 Z0.025 Z0.01 Z0.005
1.282 1.645 1.960 2.326 2.576
You may use a calculator or the common z values above.
• Round the final answer to two decimal places.
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