Suppose you are a quality control manager at a manufacturing company that produces light bulbs. The company has recently made changes to the manufacturing process, and you want to investigate whether these changes have had a significant impact on the average lifespan of the bulbs. You collect a random sample of 30 light bulbs produced under the new process and find that the sample mean lifespan is 1200 hours with a sample standard deviation of 100 hours. Additionally, you collect a random sample of 35 light bulbs produced under the old process and find that the sample mean lifespan is 1180 hours with a sample standard deviation of 90 hours. Assuming that the population standard deviations are unknown but equal, test at a 5% significance level that the average lifespan of the light bulb has changed with the new manufacturing process. NOT FOR MARKS, just a book sample question
Suppose you are a quality control manager at a manufacturing company that produces light bulbs. The company has recently made changes to the manufacturing process, and you want to investigate whether these changes have had a significant impact on the average lifespan of the bulbs.
You collect a random sample of 30 light bulbs produced under the new process and find that the sample mean lifespan is 1200 hours with a sample standard deviation of 100 hours. Additionally, you collect a random sample of 35 light bulbs produced under the old process and find that the sample mean lifespan is 1180 hours with a sample standard deviation of 90 hours. Assuming that the population standard deviations are unknown but equal, test at a 5% significance level that the average lifespan of the light bulb has changed with the new manufacturing process.
NOT FOR MARKS, just a book sample question
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