Lower and Upper Quartiles Sheet 1 - Find Lower and Upper Quartile - Calculate Interquartile Range

Oct 22, 2026

Uploaded by Mary Man

Lower and upper quartiles worksheet 1 focused on finding quartile values from several given sets of data. The worksheet instructs learners to order each dataset, determine the lower quartile, median, and upper quartile, then compute the interquartile range as the difference between upper and lower quartiles. Included examples show ordered lists and step-by-step quartile calculations for seven numbered problems, with answers provided for quartile positions and interquartile range results.

LanguageEnglish

CategoryExam

FormatPDF

Pages2

Reading Time5 min

AccessFree to download

Instructions

Task: Find quartiles and interquartile range

Example Calculations

Example data set and quartile values

Questions

1-7 data sets

Answers

Quartile and interquartile range results

LOWER AND UPPER QUARTILES SHEET 1 Find the lower and upper quartile in each of the sets of data. When you have done that, find the interquartile range. | Example {15, 23, 19, 20, 20, 22, 26} | | 4) {22, 37, 19, 25, 37, 51, 82} | | | --- | --- | --- | --- | | order {15, 19, 20, 20, 22, 23, 26} | | order | | | Lower Quartile
19 |
Median
20 | Lower Quartile | Median | | Upper Quartile
23 | Interquartile range
23 – 19 = 4 | Upper Quartile | Interquartile range | | 1) {2, 7, 4, 2, 3, 6, 11} | | 5) {6, 2, 13, 7, 6, 11, 10, 8, 2} | | | order | | order | | | Lower Quartile | Median | Lower Quartile | Median | | Upper Quartile | Interquartile range | Upper Quartile | Interquartile range | | 2) {70, 63, 67, 62, 63, 68, 59} | | 6) {109, 104, 96, 103, 98, 107} | | | order | | order | | | Lower Quartile | Median | Lower Quartile | Median | | Upper Quartile | Interquartile range | Upper Quartile | Interquartile range | | 3) {11, 4, 7, 8, 2, 4} | | 7) {14, 68, 38, 65, 36, 57, 65, 22, 41} | | | order | | order | | | Lower Quartile | Median | Lower Quartile | Median | | Upper Quartile | Interquartile range | Upper Quartile | Interquartile range | LOWER AND UPPER QUARTILES SHEET 1 ANSWERS | Example {15, 23, 19, 20, 20, 22, 26} | | 4) {22, 37, 19, 25, 37, 51, 82} | | | --- | --- | --- | --- | | order {15, 19, 20, 20, 22, 23, 26} | | order {19, 22, 25, 37, 37, 51, 82} | | | Lower Quartile
19 |
Median
20 | Lower Quartile
22 |
Median
37 | | Upper Quartile
23 | Interquartile range
23 – 19 = 4 | Upper Quartile
51 | Interquartile range
51 – 22 = 29 | | 1) {2, 7, 4, 2, 3, 6, 11} | | 5) {6, 2, 13, 7, 6, 11, 10, 8, 2} | | | order {2, 2, 3, 4, 6, 7, 11} | | order {2, 2, 6, 6, 7, 8, 10, 11, 13} | | | Lower Quartile
2 |
Median
4 | Lower Quartile
(2+6)/2 = 4 |
Median
7 | | Upper Quartile
7 | Interquartile range
7– 2 = 5 | Upper Quartile
(10+11)/2 = 10 ½ | Interquartile range
10 ½ -4 = 6 ½ | | 2) {70, 63, 67, 62, 63, 68, 59} | | 6) {109, 105, 96, 103, 98, 107} | | | order {59, 62, 63, 63, 67, 68, 70} | | order {96, 98, 103, 105, 107, 109} | | | Lower Quartile
62 |
Median
68 | Lower Quartile
98 |
Median
(103+105)/2 = 104 | | Upper Quartile
68 | Interquartile range
68 – 62 = 6 | Upper Quartile
107 | Interquartile range
107– 98 = 9 | | 3) {11, 4, 7, 8, 2, 4} | | 7) {14, 68, 38, 65, 36, 57, 65, 22, 41} | | | order {2, 4, 4, 7, 8, 11} | | order {14, 22, 36, 38, 41, 57, 65, 65, 68} | | | Lower Quartile
4 |
Median
(4+7)/2 = 5 ½ | Lower Quartile
(22+36)/2 = 29 |
Median
41 | | Upper Quartile
8 | Interquartile range
8 – 4 = 4 | Upper Quartile
(65+65)/2 = 65 | Interquartile range
65 – 29 = 36 |

FAQs

What are the lower quartile and upper quartile used for in this worksheet?

They identify the 25% and 75% positions of an ordered data set. The worksheet asks for both values before computing the interquartile range.

How is the interquartile range calculated here?

It is calculated as upper quartile minus lower quartile (IQR = Q3 − Q1). The answer section shows this difference for each numbered set.

What steps should you follow before reading off the quartiles?

First order the data values, then determine the lower quartile, median, and upper quartile from the ordered list. The worksheet’s examples demonstrate ordering and position-based quartile selection.

Oct 22, 2026

Uploaded by Mary Man