Problem

b) Electric cable is sold in reels. The length of cable on the reels can be assumed to follow a Normal distribution with mean 50 metres and standard deviation 0.5 metres. $11.9 \%$ of reels have more than $x$ metres of cable. Find the value of $x$.

Solution

Step 1 :The problem is asking for the value of \(x\) such that \(11.9\%\) of the reels have more than \(x\) meters of cable. This is a problem of finding the percentile of a normal distribution.

Step 2 :The mean (\(\mu\)) is 50 and the standard deviation (\(\sigma\)) is 0.5.

Step 3 :We know that \(11.9\% = 0.119\) is the right tail of the distribution, so we need to find the \(100\% - 11.9\% = 88.1\%\) percentile of the distribution.

Step 4 :We can use the inverse of the cumulative distribution function (CDF) of the normal distribution, also known as the quantile function, to find this value.

Step 5 :Using the given values, we find that \(x = 50.59000027017387\).

Step 6 :Final Answer: The value of \(x\) is approximately \(\boxed{50.59}\).

From Solvely APP
Source: https://solvelyapp.com/problems/28639/

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