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Statistics - Normal Distribution

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A light bulb manufacturer claims her bulbs have a population mean life of 1,000 hours. Is this claim justified at the .05 level if a random sample of 25 bulbs has a sample mean of 994 hours with a standard deviation of 30 hours? Assume the population life expectancy of the bulbs is normally distributed.

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The expert examines if light bulb manufacturer claims in statistics are normal distributed. A complete, neat and step-by-step solution is provided.

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H0: m = 1000 vs Ha: m <> 1000

Critical two-tailed z- acores at a = 0.05 are -1.96 and ...

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