Problem

The mean of a normally distributed data set is 75 with a standard deviation of 5 . Find the data value that is greater than $8 \%$ of the data. Click here to see page 1 of the table for areas under the standard normal curve. Click here to see page 2 of the table for areas under the standard normal curve. The data value that is greater than $8 \%$ of the data is $\square$. (Round to the nearest whole number as needed.)

Solution

Step 1 :Find the z-score that corresponds to the 8% percentile. Since the problem asks for the data value that is greater than 8% of the data, we need to look at the lower tail of the distribution.

Step 2 :Use a standard normal distribution table to find the z-score that corresponds to the 8% percentile. The z-score is approximately -1.41.

Step 3 :Use the z-score formula to find the corresponding data value. The z-score formula is \(Z = \frac{X - \mu}{\sigma}\), where Z is the z-score, X is the data value, \(\mu\) is the mean, and \(\sigma\) is the standard deviation.

Step 4 :Rearrange the formula to solve for X: \(X = Z\sigma + \mu\).

Step 5 :Substitute the values into the formula: \(X = -1.41*5 + 75\).

Step 6 :Calculate the above expression: \(X = -7.05 + 75\).

Step 7 :Round to the nearest whole number: \(X = 68\).

Step 8 :\(\boxed{68}\) is the data value that is greater than 8% of the data.

From Solvely APP
Source: https://solvelyapp.com/problems/4qFo3kiv5k/

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