A city installs 2000 electric lamps for street lighting.These lamps have a mean burning life of 1000 hourswith a standard deviation of 200 hours. Assume thatthe burning life is approximately normally distributed.a.) What is the probability that a lamp will not fail inthe first 700 burning hours?b.) How many lamps are expected to fail between800 and 1200 burning hours?c.) After how many burning hours would we expectapproximately 10% of the lamps to be left?

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Answered: A city installs 2000 electric lamps for…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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Suppose a population is known to be normally distributed with a mean, μ, equal to 116 and a standard deviation, σ, equal to 14. Approximately what percent of the population would be between 116 and 144? a) 47.5% b) 68% c) 13.5% d) 95% e) 34% f) 81.5%
Assume that females have pulse rates that are normally distributed with a mean of u = 76.0 beats per minute a. If 1 adult female is randomly selected, find the probability that her pulse rate is between 69 beats per min The probability is (Round to four decimal places as needed.) b. If 25 adult females are randomly selected, find the probability that they have pulse rates with a mean bet The probability is (Round to four decimal places as needed.) c. Why can the normal distribution be used in part (b), even though the sample size does not exceed 30? O A. Since the distribution is of sample means, not individuals, the distribution is a normal distribution fo OB. Since the distribution is of individuals, not sample means, the distribution is a normal distribution fo OC. Since the mean pulse rate exceeds 30, the distribution of sample means is a normal distribution fo O D. Since the original population has a normal distribution, the distribution of sample means is a norma
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4c.) Draw the graphs. Round your final answers up to 6 decimal places, if applicable. Give the correct units.
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The lifetimes of a certain brand of light bulbs are known to be normally distributed with a mean of 1,700 hours and a standard deviation of 400 hours. A random sample of 64 of these light bulbs is taken. The probability is 0.15 that the sample mean lifetime is more than how many hours? Question 3 options: 1) 1725 2) 1670 3) 1652 4) 1752
Answer d.

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