Ever since scientists started using ANOVA, the result have been represented with a bar chart for each treatment, and one-sided wisker above the plot to represent the 95% confidence interval*. This makes comparing the treatment groups easy. If the next bar is higher/lower than the wisker then its significantly different than the control (usually on the left). Then each bar is labeled with the connecting letter from the Turkey Kramer (HSD) test to make it even easier to tell which treatments are the same and different.
*Standard Error of the Mean gets used a lot too. Heck, if my 95% CI was taller than the bar I'd choose that too, its almost 2x skinnier, and makes the figure look way better.
How to make the figure.
1. Start with Fit y by X. Add your treatment variable (nominal or ordinal) and you continuous response.
2. From the Red Triangle Menu (RTM) pick Means and Std Dev
3. From the RTM, pick Compare Means, pick the right test, likely All Paris, Turkey HSD if you have more than two groups.
4. Right click on the connecting letters report, pick, Make into Data Table
5. Right click on the Means Std Dev report, pick, Make into Data Table
6. Make a new column in the connecting letters table, manually construct the letters in one column from all the letters columns. Use lower case.
7. Use Tables, Update to join your new letters column back to the Means Std Dev table. Match column, on Level.
8. Turn on Labels for the letter column
9. Rename the Level column to the name of the treatment variable.
10. Rename the Mean column to Mean Response (your response) and 95% CI. e.g. "Mean Absorbance and 95% CI", or something like that.
11. Start Graph Builder.
12. Treatment goes on the x-axis
13. Mean Treatment and the upper 95% confidence interval go on the y-axis.
14. Choose the Bar graph element (looks wrong, but wait)
15. Make the bar graph type be Interval (still looks wrong, but wait)
16. Right click inside the graph, Add, Another Bar chart.
17. In the properties of the second bar chart, from the Label drop down, choose Label by Row.
18. Label the graph Response by Treatment.
19. Change the Graph Builder Title Bar to read One Way ANOVA
20. Click on the legend, and change the bar color too black.
21. From RTM, Save Script to Data Table.
22. From RTM in the tables box, Copy Table script.
23. In your original source data table's Table Box RTM, pick new script
24. In the dialog give the script a title, like, "Figure 1". and past the script in the lower window.
25. If your data changes. Do all this over again, because the script you just saved isn't dynamic, but at least it's a road map, kind of, to how you make the figure.
The reason only scientists use this figure is because it practically takes a PhD. to keep all the steps straight in order to get this figure right. (Note, its way easier to do this with a sharpie and graph paper.)
If the 25 step process is just a little much, or left you stuck on some vague parts that probably needed their own 25 step sub-processes. Just run the script below. Hopefully the annotation helps if you want to customize it for your frequent figures.
Names Default To Here( 1 );
//make sure there is a table open, if not open one
dtlist=Get Data Table List();
picker=expr( File = Pick File("Select JMP File","$SAMPLE_DATA",{"JMP Files|jmp;", "All Files|*"},1,0,"",));Try( Open( File[i] ) );
if(nitems(dtlist)==0, picker, dt=current data table());
dtname=dt<<GET name="">0,
insert into(str, ",", ncomma+1);
ncomma--;);
concat_vals[j] = str;);
Show( concat_vals );/// The letters are now a list in the order of the levels from table 1
/// Put the letters back into the table
dt1 << New Column( "Letters", Character, "Nominal", Set Values( concat_vals ) );
//
//Get the means and confidence intervals from the report as a table
dt2=Report( platform )[Outline Box( "Means and Std Deviations" )][Table Box( 1 )] << Make Into Data Table;
dt2<<SET name=""></SET></GET>
Sam,
In academic papers and research and development, this graph is very common. Other formats may be more informative, however normative wins. Here is a link to a whole raft of figure from papers published in high impact factor journal. As you can see, this figure type occurs fairly often.
Published scientific papers use this format frequently
Regarding intervals: It's definitely the 95% confidence intervals, take a look at the table that the graph is run against
TBH, I am a scientist and I have never seen the results of an ANOVA presented this way. i don't find the chart intuitive, and the scale is all wrong. In ANOVA you really want the scale of the data, for visualization, to be the range of the data, or a +/- k standard deviation range around the data (k somewhere in the 2-4 range). The plot above mostly focuses on proportional differences by showing a bar for the mean and with zero on the y-axis.
It also looks like you are using the standard deviation from each group to construct the error bars, but the Tukey-HSD used the pooled standard deviation, doesn't it? That's what the diamonds in the Oneway plot use, also, and the width of the diamond varies because of the number of observations in the group.
I think it is better, for the plot you constructed, to stretch the Y-axis so the the focus on on the location of the mean result.
Is this just a way to get around having to explain the "circles" in the Oneway plot that are used to which groups are similar or statistically different?
How about this plot instead?
I played around with your resulting table, created two columns to indicate if the row was in group "a" or "b" and then created this dashboard.
