Compound bar chart - to round or not round percentages?

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SUMMARY

The discussion focuses on the methodology for rounding percentages in a compound bar chart where initial data values are integers. The user proposes rounding to two significant figures and adjusting the largest percentage to ensure the total equals 100%. The example provided illustrates how rounding can lead to discrepancies, specifically when the sum of rounded percentages does not equal 100%. The consensus is to round to the nearest whole number and adjust the largest percentage to account for any discrepancies.

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Homework Statement


Hi,
My task is to draw a compound bar chart. As I understand, with this type of bar chart; each group of data is represented by a single bar which is equivalent to 100%. The sub data within that group is divided into a percentage of the total 100% and drawn into the grouping bar, splitting the bar into percentage counterparts of the whole bar.

The problem is for some of my data which initially are integers but when calculating percentages become fractions/decimals (some repeating). I don't know how to use this data when incorperating into my graph. Do I round up or down? or try to best draw them into my graph.

Normally I would round my answer to the same number of dp or sf as the lowest value in the question. However in this case, my initial numbers are integers, so if I round up or down to the same number of SF or DP, the total sum of my percentages do not add up to 100%.

In this case, (similar to if I were doing a pie chart) do I round to the nearest whole number and than add or subtract whatever remains from the largest percentage value as it would make the least diff?

Homework Equations


Imagine a table below:

Mon Tues Wed
Red 7 (30.'43%) 3 (18.75%) 2 (20%)
Blue 10 (43.'47%) 7 (43.75%) 6 (37.5%)
Black 6 (26.'08%) 6 (37.5%) 5 (50%)
Total 23 (100%) 16 10

The Attempt at a Solution



Round the numbers to 2 sf and add or subtract the extra from the largest percentage.
So for monday
Red: 30
Blue: 43
Black: 26
total: 99

Add remaining 1% to blue (43+1=44) to now have a total of 100% as it makes the least difference adding to largest percentage.

Would this be the correct method?

Thanks in advance
 
Last edited:
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Draw them as accurate as possible (a computer will do that anyway, by hand see how accurate you can draw it, I guess .5% are not visible), and display the percentages rounded to integers. The sum is 100%, even if 30+43+26=99, that is okay.
 

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