8.8. A manufacturing company of light bulb claims that an average light bulb lasts 500 days....

8.8. A manufacturing company of light bulb claims that an average light bulb lasts 500 days. A contractor randomly selects 30 bulbs for testing. The sampled bulbs last an average of 490 days, with a standard deviation of 100 days. If the claim were true, what is the probability that 30 randomly selected bulbs would have an average life of no more than 490 days? [10]

Expert Solution

Here we use the concept of Normal Distribution , calculate the Z score, then calculate the probability

orchestra answered 2 years ago

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