The manager of a computer retails store is concerned that his suppliers have been giving him laptop computers with lower than average quality. His research shows that replacement times for the model laptop of concern are normally distributed with a mean of 3.2 years and a standard deviation of 0.5 years. He then randomly selects records on 35 laptops sold in the past and finds that the mean replacement time is 3 years. Assuming that the laptop replacment times have a mean of 3.2 years and a standard deviation of 0.5 years, find the probability that 35 randomly selected laptops will have a mean replacment time of 3 years or less. P(x-bar < 3 years) =  Enter your answer as a number accurate to 4 decimal places.   The amounts of nicotine in a certain brand of cigarette are normally distributed with a mean of 0.963 g and a standard deviation of 0.315 g. The company that produces these cigarettes claims that it has now reduced the amount of nicotine. The supporting evidence consists of a sample of 30 cigarettes with a mean nicotine amount of 0.9 g. Assuming that the given mean and standard deviation have NOT changed, find the probability of randomly seleting 30 cigarettes with a mean of 0.9 g or less. P(x-bar < 0.9 g) =  Enter your answer as a number accurate to 4 decimal places.

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
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Chapter1: Starting With Matlab
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The manager of a computer retails store is concerned that his suppliers have been giving him laptop computers with lower than average quality. His research shows that replacement times for the model laptop of concern are normally distributed with a mean of 3.2 years and a standard deviation of 0.5 years. He then randomly selects records on 35 laptops sold in the past and finds that the mean replacement time is 3 years.

Assuming that the laptop replacment times have a mean of 3.2 years and a standard deviation of 0.5 years, find the probability that 35 randomly selected laptops will have a mean replacment time of 3 years or less.
P(x-bar < 3 years) = 
Enter your answer as a number accurate to 4 decimal places.

 

The amounts of nicotine in a certain brand of cigarette are normally distributed with a mean of 0.963 g and a standard deviation of 0.315 g. The company that produces these cigarettes claims that it has now reduced the amount of nicotine. The supporting evidence consists of a sample of 30 cigarettes with a mean nicotine amount of 0.9 g.

Assuming that the given mean and standard deviation have NOT changed, find the probability of randomly seleting 30 cigarettes with a mean of 0.9 g or less.
P(x-bar < 0.9 g) = 
Enter your answer as a number accurate to 4 decimal places.

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