Go to content
The lower quartile, median and upper quartile are usually denoted by Q_1, Q_2 and Q_3. To find them you must first arrange the data in order of size.
If n is odd, then Q_2 is the \frac{1}{2}(n+1)th value. If n is even the median is halfway between the \frac{1}{2}nth value and the next.
To find Q_1 find the median of the lower half of the data. To find Q_3, find the median of the upper half of the data. You can get a better display of the maths by downloading special TeX fonts from jsMath. In the meantime, we will do the best we can with the fonts you have, but it may not be pretty and some equations may not be rendered correctly.

Glossary

median

the middle value of a set of data that has been arranged in order of magnitude; half the data values are above it and half are below.

quartile

In an ordered set of data 25% are below the first (Q1), 50% are below the second (Q2), 75% are below the third (Q3).

union

The union of two sets A and B is the set containing all the elements of A and B.

Full Glossary List

This question appears in the following syllabi:

SyllabusModuleSectionTopicExam Year
AQA A-Level (UK - Pre-2017)S1Summarising dataMeasures of location-
AQA AS Maths 2017StatisticsData Presentation and InterpretationMeasures of Central Tendency-
AQA AS/A2 Maths 2017StatisticsData Presentation and InterpretationMeasures of Central Tendency-
CBSE XI (India)Statistics and ProbabilityStatisticsRange, mean deviation, variance and standard deviation of grouped data-
CCEA A-Level (NI)S1Summarising dataMeasures of location-
CIE A-Level (UK)S1Summarising dataMeasures of location-
Edexcel A-Level (UK - Pre-2017)S1Summarising dataMeasures of location-
Edexcel AS Maths 2017StatisticsMeasures of DataMeasures of Central Tendency-
Edexcel AS/A2 Maths 2017StatisticsMeasures of DataMeasures of Central Tendency-
I.B. Standard Level5Summarising dataMeasures of location-
Methods (UK)M14Summarising dataMeasures of location-
I.B. (MSSL)6Summarising dataMeasures of location-
OCR A-Level (UK - Pre-2017)S1Summarising dataMeasures of location-
OCR AS Maths 2017StatisticsCentral Tendency and VariationMeasures of Central Tendency-
OCR MEI AS Maths 2017StatisticsCentral Tendency and VariationMeasures of Central Tendency-
OCR-MEI A-Level (UK - Pre-2017)S1Summarising dataMeasures of location-
Pre-U A-Level (UK)ProbSummarising dataMeasures of location-
Scottish (Highers + Advanced)HSSummarising dataMeasures of location-