# Question: Lightbulbs The lifetime of lightbulbs has a mean of 1500

Lightbulbs: The lifetime of lightbulbs has a mean of 1500 hours and a standard deviation of 100 hours. A sample of 50 lightbulbs is tested.

a. What is the probability that the sample mean lifetime is greater than 1520 hours?

b. What is the probability that the sample mean lifetime is less than 1540 hours?

c. What is the probability that the sample mean lifetime is between 1490 and 1550 hours?

a. What is the probability that the sample mean lifetime is greater than 1520 hours?

b. What is the probability that the sample mean lifetime is less than 1540 hours?

c. What is the probability that the sample mean lifetime is between 1490 and 1550 hours?

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