Examples of a marginal plot
main topics     interpreting results     session command     see also 

As a quality control engineer for a camera battery manufacturer, you want to examine the relationship between flash recovery time (minimum time between flashes) and the voltage remaining in a camera battery. You create the three types of marginal plots to look at the distribution of each measurement.

With histograms

1    Open the worksheet BATTERIES.MTW.

2    Choose Graph > Marginal Plot.

3    Choose With Histograms, then click OK.

4    In Y Variable, enter FlashRecov.

5    In X Variable, enter VoltsAfter.

6    Click Labels, then click the Histogram Labels tab.

7    Check Label histogram bars with y-value, then click OK in each dialog box.

With boxplots

1    Open the worksheet BATTERIES.MTW.

2    Choose Graph > Marginal Plot.

3    Choose With Boxplots, then click OK.

4    In Y Variable, enter FlashRecov.

5    In X Variable, enter VoltsAfter. Click OK.

With dotplots

1    Open the worksheet BATTERIES.MTW.

2    Choose Graph > Marginal Plot.

3    Choose With Dotplots, then click OK.

4    In Y Variable, enter FlashRecov.  

5    In X Variable, enter VoltsAfter. Click OK.

Interpreting the results

You can look at the scatterplot as well as the distributions of both x and y using histograms, boxplots, or dotplots.

·    The scatterplots show a possible negative correlation between FlashRecov and VoltsAfter; that is, flash recovery time increases as the voltage decreases.

·    The marginal distributions have clusters of points (about 5.0 - 5.5 for FlashRecov and about 1.1 for VoltsAfter), especially obvious with the histograms and dotplots.

Tip

To see information for an individual symbol, box, or bar, hover your cursor over it.