The formula to calculate the 40th percentile (P40) is:
P40 = \(1 + (n - 1) \times 0.40\)
Where:
A 40th percentile is a statistical measure that indicates the value below which 40 percent of the data points in a dataset may be found. In other words, 40 percent of the observations are less than or equal to this value. It is often used in statistics to provide a relative standing of a value within a dataset.
Example 1:
Calculation:
P40 = \(1 + (50 - 1) \times 0.40 = 1 + 49 \times 0.40 = 1 + 19.6 = 20.6\)
Example 2:
Calculation:
P40 = \(1 + (100 - 1) \times 0.40 = 1 + 99 \times 0.40 = 1 + 39.6 = 40.6\)
