Question

Write short notes on Percentiles.

Answer 1

Not to be confused with Percentile function.

A percentile (or a centile) is a measure used in statistics indicating the value below which a given percentage of observations in a group of observations falls. For example, the 20th percentile is the value (or score) below which 20% of the observations may be found.
The term percentile and the related term percentile rank are often used in the reporting of scores from norm-referenced tests. For example, if a score is at the 86th percentile, where 86 is the percentile rank, it is equal to the value below which 86% of the observations may be found (carefully contrast with in the 86th percentile, which means the score is at or below the value below which 86% of the observations may be found - every score is in the 100th percentile). The 25th percentile is also known as the first quartile(Q1), the 50th percentile as the median or second quartile (Q2), and the 75th percentile as the third quartile (Q3). In general, percentiles and quartiles are specific types of quantiles.

Answer 2

Percentiles:

• Percentiles are determined using the formula n = (P/100) x N,
• where P represents the percentile,
• N is the number of values in a data collection (ordered from least to largest), and
• n represents the ordinal rank of a particular value.
• Percentiles are commonly used to decipher test results and biometric measures. Percentiles and percentages are not the same things.