Question

# The population mean waiting time to check out of a supermarket has historically been 4 minutes....

The population mean waiting time to check out of a supermarket has historically been 4 minutes. In an effort to reduce the waiting time, you, as store manager, conducted an experiment with infrared cameras that use body heat and in-store software to determine how many lanes should be opened. To test the effectiveness of this process, you selected a random sample of 100 customers and recorded their waiting time. For this sample, the mean waiting time to check out was 3.3 minutes, with a sample standard deviation of 2.0 minutes.

At the 0.05 level of significance, is there evidence that the population mean waiting time to check out is less than 4 minutes?

1. State your null and alternative hypothesis
2. What is your conclusion based on this test? Interpret the meaning of the p-value in this case.
3. Based on these results, what is your decision as store manager.

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