Choosing how to display data questions

[horizon]

I can never do the questions where they ask you to choose the best way to display data!!

For e.g.

The relationship between the variables size (small, medium, large, extra large, extra extra large) and number ordered is best displayed by


A.   a parallel boxplot
B.   a back-to-back stemplot
C.   a histogram
D.   a bar chart
E.   a scatterplot

The answer is D, but I chose A.  I still don't see how a bar chart would work- isn't that only for univariate data?
How should I approach these questions, because I always end up confused!

[some dude]

what i aways do is follow this rule:

1-categorical and categorical=segmented bar chart
2-categorical and numerical=parallel boxplots
3-numerical and numerical=scatterplot

you can also use back-to-back stem and leaf plot for number 2 if you have only two categories, but even then boxplots are prefered.

[horizon]

Thanks for your reply, your summary has helped!