A manufacturer of light bulbs claims that its light bulbs have a mean life of 1520...

A manufacturer of light bulbs claims that its light bulbs have a mean life of 1520 hours. If a random sample of 40 bulbs is tested and has an average life of 1500 hours and the standard deviation is 80 hours, is there sufficient evidence to claim that the mean life is different than the manufacturer's claim? Use alpha = 0.01.
Calculate the test statistic.
Calculate a confidence interval for the true mean light bulb life. Use the level of confidence that matches the hypothesis test you conducted above at the alpha = 0.01 significance level. Do NOT interpret.

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orchestra answered 1 year ago

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