The manager of a computer retails store is concerned that his suppliers have been giving him laptopcomputers with lower than average quality. His research shows that replacement times for themodel laptop of concern are normally distributed with a mean of 3.7 years and a standard deviationof 0.4 years. He then randomly selects records on 42 laptops sold in the past and finds that themean replacement time is 3.6 years.Assuming that the laptop replacement times have a mean of 3.7 years and a standard deviation of0.4 years, find the probability that 42 randomly selected laptops will have a mean replacement timeof 3.6 years or less.P(M < 3.6 years) =Enter your answer as a number accurate to 4 decimal places. NOTE: Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted.Based on the result above, does it appear that the computer store has been given laptops of lowerthan average quality?O No. The probability of obtaining this data is high enough to have been a chance occurrence.O Yes. The probability of this data is unlikely to have occurred by chance alone.

Given that the mean is 3.7 years and the standard deviation is 0.4 years. Sample size is 42.…

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 3.7 years and a standard deviation of 0.4 years. He then randomly selects records on 42 laptops sold in the past and finds that the mean replacement time is 3.6 years. Assuming that the laptop replacement times have a mean of 3.7 years and a standard deviation of 0.4 years, find the prohahility that 13 rando

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 3.7 years and a standard deviation of 0.4 years. He then randomly selects records on 42 laptops sold in the past and finds that the mean replacement time is 3.6 years. Assuming that the laptop replacement times have a mean of 3.7 years and a standard deviation of 0.4 years, find the prohahility that 13 rando

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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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 4.1 years and a standard deviation of 0.5 years. He then randomly selects records on 42 laptops sold in the past and finds that the mean replacement time is 3.9 years.Assuming that the laptop replacement times have a mean of 4.1 years and a standard deviation of 0.5 years, find the probability that 42 randomly selected laptops will have a mean replacement time of 3.9 years or less.P(M < 3.9 years)
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 3.6 years and a standard deviation of 0.4 years. He then randomly selects records on 48 laptops sold in the past and finds that the mean replacement time is 3.4 years. Assuming that the laptop replacement times have a mean of 3.6 years and a standard deviation of 0.4 years, find the probability that 48 randomly selected laptops will have a mean replacement time of 3.4 years or less. P(M < 3.4 years)=__________
Fran is training for her first marathon, and she wants to know if there is a significant difference between the mean number of miles run each week by group runners and individual runners who are training for marathons. She interviews 42 randomly selected people who train in groups and finds that they run a mean of 47.1 miles per week. Assume that the population standard deviation for group runners is known to be 4.4 miles per week. She also interviews a random sample of 47 people who train on their own and finds that they run a mean of 48.5 miles per week. Assume that the population standard deviation for people who run by themselves is 1.8 miles per week. Test the claim at the 0.01 level of significance. Let group runners training for marathons be Population 1 and let individual runners training for marathons be Population 2. Step 2 of 3 : Compute the value of the test statistic. Round your answer to two decimal places.
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 3.3 years and a standard deviation of 0.4 years. He then randomly selects records on 25 laptops sold in the past and finds that the mean replacement time is 3.2 years.Assuming that the laptop replacement times have a mean of 3.3 years and a standard deviation of 0.4 years, find the probability that 25 randomly selected laptops will have a mean replacement time of 3.2 years or less.P(M < 3.2 years) = Enter your answer as a number accurate to 4 decimal places. NOTE: Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted.Based on the result above, does it appear that the computer store has been given laptops of lower than average quality? No. The probability of obtaining this data is high enough…
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Pilots who cannot maintain regular sleep hours due to their work schedule often suffer from insomnia. A recent study on sleeping patterns of pilots focused on quantifying deviations from regular sleep hours. A random sample of 28 commercial airline pilots was interviewed, and the pilots in the sample reported the time at which they went to sleep on their most recent working day. The study gave the sample mean and standard deviation of the times reported by pilots, with these times measured in hours after midnight. (Thus, if the pilot reported going to sleep at p.m., the measurement was -1.) The sample mean was 0.8 hours, and the standard deviation was 1.6 hours. Assume that the sample is drawn from a normally distributed population. Find a 90% confidence interval for the population standard deviation, that is, the standard deviation of the time (hours after midnight) at which pilots go to sleep on their work days. Then give its lower limit and upper limit.
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