Read a graph in two steps
First see what is given, then work out what it means.
Two days in Jodhpur
The graph shows the temperature every 3 hours on two days in Jodhpur, Rajasthan.
One cluster for each time of day, one colour for each data set.
You see a graph for the first time. What should you do first?
What this lesson covers
The idea
To make sense of a graph, first identify what is given (how it is organised, the scale used and the patterns shown), then analyse and interpret each observation to infer conclusions.
Two days in Jodhpur
The graph shows the temperature every 3 hours on two days in Jodhpur, Rajasthan.
You see a graph for the first time. What should you do first?
- Say what it means
- Find out what is given: what is along the bottom, the scale, the colours
- Add up all the numbers
Step 1 or Step 2?
Look at the graph. Sort each sentence: does it tell what the graph shows (Step 1), or is it a conclusion we work out (Step 2)?
Identify first, then infer
Step 1, identify: how the graph is organised, the scale used, and the patterns it shows.
Step 2, infer: think about each observation and work out a conclusion.
To make sense of a graph, first identify what is given (how it is organised, the scale used and the patterns shown), then analyse and interpret each observation to infer conclusions.
- Step | Example from the graph
- 1. Identify | The tallest columns are at 3 pm; Day 2 is taller in every cluster
- 2. Infer | Day 2 was probably in a hotter month
Notes
To make sense of a graph, first identify what is given (how it is organised, the scale used and the patterns shown), then analyse and interpret each observation to infer conclusions.
Check yourself
Which of these belongs to Step 1 (identify)?
Which of these needs Step 2 (infer)?
At 3 pm, how many degrees hotter was Day 2 than Day 1?
Answer: 9
43 − 34 = 9 °C.
On Day 2 the temperature was 30 °C at 6 am and 43 °C at 3 pm. By how many degrees did it rise?
Answer: 13
43 − 30 = 13 °C.
- Day 2 may be from a summer month. That is a conclusion we work out, so it belongs to Step 2.
- The side scale goes up in steps of 10 °C — correct. Yes! The scale is part of what is given in the graph.
- The tallest column must be a mistake. That is a guess. Step 1 only notes what the graph shows.
- Day 1 at 12 am is 20 °C. This is read straight from a column. It is Step 1.
- Day 2 was probably in a hotter month than Day 1 — correct. Yes! The graph shows temperatures. The month is something we work out from them.
- Day 1 is blue and Day 2 is orange. The colours are given in the graph. It is Step 1.