An electric company has been selling a bulb, which was advertised as having an average life of 1, 500 hours. Assume that the lifetime of these bulbs is normally distributed with a standard deviation of 800 hours. A random sample of 16 bulbs from this manufacturing process was tested ad their lifetimes were recorded. a. What is the probability that the sample mean is between 1,250 and 1,750 hours? b. A lot consisting of 10,000 bulbs will be rejected if the sample mean based on 16 bulbs is 1,200 hours or less.What is the probability that the lot will be rejected? 2. A manufacturer of a low-tar cigarette claims that its cigarettes contain an average of 16.3 mg. of tar with a standard deviation of 3.1 mg per cigarette. What is the probability that in a sample of 225 cigarettes, the sample mean (of tar in cigarette in mg.) is higher than 15.9?
An electric company has been selling a bulb, which was advertised as having an average life of 1, 500 hours. Assume that the lifetime of these bulbs is normally distributed with a standard deviation of 800 hours. A random sample of 16 bulbs from this manufacturing process was tested ad their lifetimes were recorded. a. What is the probability that the sample mean is between 1,250 and 1,750 hours? b. A lot consisting of 10,000 bulbs will be rejected if the sample mean based on 16 bulbs is 1,200 hours or less.What is the probability that the lot will be rejected? 2. A manufacturer of a low-tar cigarette claims that its cigarettes contain an average of 16.3 mg. of tar with a standard deviation of 3.1 mg per cigarette. What is the probability that in a sample of 225 cigarettes, the sample mean (of tar in cigarette in mg.) is higher than 15.9?
Chapter8: Sequences, Series,and Probability
Section8.7: Probability
Problem 11ECP: A manufacturer has determined that a machine averages one faulty unit for every 500 it produces....
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- An electric company has been selling a bulb, which was advertised as having an average life of 1, 500 hours. Assume that the lifetime of these bulbs is
normally distributed with a standard deviation of 800 hours. A random sample of 16 bulbs from this manufacturing process was tested ad their lifetimes were recorded.
a. What is the probability that the sample
b. A lot consisting of 10,000 bulbs will be rejected if the sample mean based on 16 bulbs is 1,200 hours or less.What is the probability that the lot will be rejected?
2. A manufacturer of a low-tar cigarette claims that its cigarettes contain an average of 16.3 mg. of tar with a standard deviation of 3.1 mg per cigarette. What is the probability that in a sample of 225 cigarettes, the sample mean (of tar in cigarette in mg.) is higher than 15.9?
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