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Author Question: The time it takes a mechanic to change the oil in a car is exponentially distributed with a mean of ... (Read 124 times)

Melani1276

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on: Jun 24, 2018
The time it takes a mechanic to change the oil in a car is exponentially distributed with a mean of 5 minutes.
 a. What is the probability density function for the time it takes to change the oil?
  b. What is the probability that it will take a mechanic less than 6 minutes to change the oil?
  c. What is the probability that it will take a mechanic between 3 and 5 minutes to change the oil?

Question 2

A coal company wants to determine a 95 confidence interval estimate for the average daily tonnage of coal that it mines. Assuming the company reports that the standard deviation of daily output is 200 tons, how many days should it sample so that the margin of error will be 39.2 tons or less?


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Hikerman221

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Reply #1 on: Jun 24, 2018
Answer to Question 1

a. f(x) = (1/5) e-x/5 for x  0
b. .6988
c. .1809

Answer to Question 2

100


Melani1276

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Reply 2 on: Jun 24, 2018
Gracias!

raenoj

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Reply 3 on: Yesterday
Excellent

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