Yahoo Answers is shutting down on 4 May 2021 (Eastern Time) and the Yahoo Answers website is now in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
i don't know how to do this..?
A muffler company advertises that u will receive a rebate if it takes longer than 30min to replace your muffler. Experience has shown that the time taken to replace a muffler is approximately normally distributed with a mean of 25min and a standard deviation of 2.5min. What proportion of customers receive rebates?
The answer is 0.0228.
Then, another follow up question arises,
What should be the rebate-determining time of 30min in previous Q be changed to if the company wishes to provide only 1% of the customers with a rebate?
The answer is 25+2.33(2.5)
I don't understand it at all
1 Answer
- Anonymous9 years agoFavourite answer
Use a normal distribution table or graphic calculator
Pr(X>30) = Pr(Z>2) = 0.0228
and use inverse normal
Pr(Z > a)= 0.01 ----> a = 2.33 ---> X = 25+2.33(2.5) = ..