A LED company claims that the average life of the LED light bulbs it
manufactures is 1, 500 hours with a standard deviation of 500 hours. If a random sample of 40 bulbs is chosen, what is the probability that the sample mean will be:
a. greater than 1, 400 hours?
b. less than 1, 400 hours?
Let the average life of the LED light bulb:
Given
a)
b)
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