Alexis K.

asked • 10/07/20

What is the proportion

It is estimated that the mean life span of concrete drill bits is 20 hours. Suppose a construction company purchases drill bits that have a lifespan that is approximately normally distributed with a mean equal to 20 hours and and a standard deviation of 2 hours.


questions:

- What is the proportion of the company’s drill bits will fail before 18 hours of use?


- What is the proportion will last at least 18 hours?


- What proportion will have to be replaced after more than 25 hours of use?

1 Expert Answer

By:

Still looking for help? Get the right answer, fast.

Ask a question for free

Get a free answer to a quick problem.
Most questions answered within 4 hours.

OR

Find an Online Tutor Now

Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.