Plotting means

[Tracy Lam]

Hi -- I am very new to Stata and statistics in general. I would like to plot the means of test scores across three experimental groups. The test scores are not standardized. My question is whether I plot them as unstandardized or standardized test scores. If I were to plot it standardized, wouldn't all the means be 0? Does it make sense to plot unstandardized means?

Any help is much appreciated!

Thanks,
Tracy

[Evelyn Ersanilli]

Dear Tracy

Why do you want to plot the means; what do you want to learn from / show with the plot?
Why do you think standardisation could be helpful or important?

If you standardise the variable for the pooled dataset (so all 3 groups together), the mean of each group may differ from zero if the groups have different mean scores.
If you standardise the variable within each of the three groups than the means for all groups would indeed be 0.

[Nick Cox]

Evelyn gave good advice.

Almost always you should plot means together at least some indication of variability in the data, if not the data themselves. dotplot makes this easy and stripplot (SSC) is (bar minor details) a more versatile user-written alternative. Those don't exhaust the possibilities.

[Tracy Lam]

Thank you, Evelyn and Nick. This is incredibly helpful and gave me some things to think about.