Pressure values measured by various probes in the test section of a wind tunnel to obtain the freestream velocity have been given in the table below. The researcher who made the measurements concluded that the $8$ th reading had a value of $-3\mathrm{.}625$ as the "deviation from the mean" and eliminated the data point based on the Chauvenet criterion. However, she later realized that she used the factor $"\frac{1}{n}"$ instead of $"\frac{1}{n-1}"$ in the calculation of standard deviation, which was used for data sets with a total number of data points less than $20.$ Find the value of the $8$th reading and determine if the elimination is actually necessary.

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