90percentile

The 90th percentile is a measure used in statistics to indicate the value below which 90% of a dataset falls. It is one of many percentile ranks that divide a probability distribution into 100 equal parts. For example, if a test score is at the 90th percentile, it means that 90% of the test-takers scored lower than that particular score, and 10% scored higher.

Calculating the 90th percentile involves ordering the data from smallest to largest. Then, a specific position is determined based on the number of data points. For a dataset with 'n' observations, the position of the 90th percentile is often calculated as 0.90 * (n + 1). If this result is an integer, the value at that position is the 90th percentile. If it's not an integer, interpolation between the values at the surrounding integer positions is typically used.

Percentiles are widely applied in various fields, including education, economics, and healthcare. In education, they are used to compare student performance. In economics, they can show income distribution. In healthcare, percentiles help in understanding growth charts for children. The 90th percentile is particularly useful for identifying high values or outliers within a dataset, providing insight into the upper range of observed data. It is important to note that the interpretation of a percentile is always relative to the specific dataset it is derived from.