Idea 10of 22Builds onRead a middle piece
Stretch each bar to one whole
How can stacked bars compare groups of different sizes?
Today you'll discover
- what a 100% stacked bar is
- how heights become shares
- when two pieces line up
Think firstTwo rooms, two sizes
The bars are different heights. How can they compare shares fairly?
Decide first, then press Next. Watch the bars stretch, then compare one piece across them.
Room 12 and Room 14's stacked bars on a count scale, 20 and 25 tall. Then both bars stretch to the same height on a scale from 0 to 1, and the pieces show shares: walk 0.40 and 0.36, bus 0.30 and 0.24, car 0.20 and 0.20, bike 0.10 and 0.20. Dashed lines run across both bars at the walk piece. The last step shows Grade 4 and Grade 5's recess bars.
See the whole ideathe big idea and the key word, in one place
The big idea
A 100% stacked-bar graph stretches every bar to one whole, so piece heights compare as shares.
Compare themOn counts, Room 14's bar is taller just because it is a bigger room. Stretched to one whole, the pieces show shares, which compare fairly.
Easy to get wrongA 100% stacked bar hides how big each group was. Write the group sizes under the bars: 20 students, 25 students.
Key word
- 100% stacked-bar graph
- a stacked-bar graph where every bar is stretched to the same height, one whole, so each piece shows a share
Ready to use it?
- Read shares from a 100% stacked-bar graph.
- Compare one part across groups of different sizes.