Centile
- A centile gives the position of a value relative to other values in a dataset, expressed as a percentage.
- It shows the percentage of observations that a value is greater than or equal to (e.g., 50th centile means ≥ 50% of values).
- Commonly used to compare individuals and groups and in areas such as medical and health research.
Definition
Section titled “Definition”Centile is a term used in statistics to describe the relative standing of a value within a dataset. It is a measure of where a particular value falls in relation to the rest of the values in the dataset, and is typically expressed as a percentage.
Explanation
Section titled “Explanation”A centile indicates the percentage of observations in a dataset that are less than or equal to a given value. For example, a value at the 50th centile is greater than or equal to 50% of the other values; a value at the 75th centile is greater than or equal to 75% of the other values. Centiles help to understand the distribution of values within a dataset and to compare the relative standing of different values or groups.
Examples
Section titled “Examples”Example: 1000-value dataset
Section titled “Example: 1000-value dataset”If a dataset contains 1000 values and a particular value falls at the 50th centile, it means that it is greater than or equal to 50% of the other values in the dataset. Similarly, a value at the 75th centile is greater than or equal to 75% of the other values.
Example: children’s heights within a group
Section titled “Example: children’s heights within a group”If a group of children are measured for their height and the resulting dataset is used to calculate the centile for each child’s height, a child with a height at the 50th centile would be taller than or equal to 50% of the other children in the group, while a child with a height at the 75th centile would be taller than or equal to 75% of the other children in the group.
Example: comparing two groups
Section titled “Example: comparing two groups”If the height centiles of two groups of children are calculated and compared, the comparison can show relative standing between groups. For instance, if one group has a higher percentage of children with a height at the 75th centile compared to the other group, it indicates that the first group is taller on average than the second group.
Use cases
Section titled “Use cases”- Measuring performance or characteristics of a group (for example height, weight, intelligence, or income).
- Comparing the distribution of values between different groups.
- Medical and health research, for measuring growth and development and identifying potential health issues.