**Percentile Rank Formula**

Rank = (P / 100) * N

Where,

P is Percentile,

N is Number of items

**Decile Formula**

Where,

L is lower boundary

F is cummulative frequency

f is frequency

N is total frequency

k = nth decile, where n = 1, 2, 3, 4, 5, 6, 7, 8, and 9

## How to find percentile and ordinal rank ?

Example Question: Find out where the 25^{th} percentile is in the below list.

Score | Rank |
---|---|

30 | 01 |

33 | 02 |

43 | 03 |

53 | 04 |

56 | 05 |

67 | 06 |

68 | 07 |

72 | 08 |

**Step 1:**Arrange the data in ascending order

30, 33, 43, 53, 56, 67, 68, 72

**Step 2:**Calculate what rank is at the 25th percentile by using the following formula

Rank = P / 100 * (N)

Where P is Percentile = 25, N is Number of items = 8

Rank = 25 / 100 * (8) = 0.25 * 8 = 2.

The 25^{th} percentile is the average of the values in the 1^{th} and 2^{th} positions (33 and 43 respectively).

The 25^{th} percentile is (33 + 43) / 2 = 38

In this case, the 25th percentile score is 38, which makes more sense as its in the middle of 43 and 33.