Students in Ms. Cameron's grade 4 class were wondering if a broken line can be used anywhere in the range on the y - axis when creating a broken line graph? They understand that the broken line can be used at the 0 on the broken line but what if there is a large gap in the data from 100 - 200? What do we do? The text book and mathematics dictionary do not answer these questions.

Thank you.
Lori Samara, Kristi Cameron and the 4th grade students

Hi,

If I understand your question you have a large gap in the y-values of the data for which you want to make a broken line graph. I have seen this graphed in various ways. One way, as in the diagram below, is to indicate a change in scale on the y-axis between 100 and 200 by "breaking" the y-axis with a wiggle between 100 and 200. I have joined the points with y-values 100 and 200 with a line segment also containing a wiggle. I have seen this done with a dashed line or by not joining the points at all. I think the important fearure of the graph is that the reader immediately see that there is something unusual happening between 100 and 200.

Cheers,
Penny

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