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Last month the waiting time at the drive through window of a fast-food restaurant was 3.7 minutes
Last month the waiting time at the drive-through window of a fast-food restaurant was 3.7 minutes. The franchise has installed a new process intended to reduce waiting time. After the installation, a random sample of 64 orders is selected. The sample mean waiting time is 3.57 minutes with a sample standard deviation of 0.8 minutes. At a 5% level of significance, is there sufficient evidence that the population mean waiting time is now less than 3.7 minutes? What is your conclusion?
The life in hours of an electronic sensor is known to be approximately Normally distributed
The life in hours of an electronic sensor is known to be approximately Normally distributed, with population standard deviation = hours. A random sample of 10 sensors resulted in the following data: 500,550,560,575,525,505,510,540,550,545.
- Is there evidence to support the claim that mean life exceeds 520 hours? Use a fixed-level test with alpha = 0.05.
- What is the P-value of this test? Conclude the same of part (a)?
- What is the Beta-value for this test if the true mean life is 535 hours?
- What sample size would be required to ensure that Beta does not exceed 0.10 if the true mean life is 540 hours?
- Construct a 95% one-sided lower CI on the mean life.
- Use the CI found in part e) to test the hypothesis.