Simple Statistics with Scatter Plot and Reference Lines

This SAS^© script defines a `STATGRAPH` template named `simpleStats` for data visualization. It generates a scatter plot displaying the relationship between the manufacturer's suggested retail price (msrp) and highway fuel consumption (mpg_highway), grouped by vehicle type. The graph is enhanced with reference lines: a vertical one indicating the median of `msrp`, and two horizontal ones for the mean of `mpg_highway` plus/minus one standard deviation. A legend is included for the type groups, and a dynamic footnote displays the min/max weight range of the vehicles. The template is then rendered using the `sashelp.cars` table.

Data Analysis

Type : SASHELP

The script uses the `cars` table from the internal `sashelp` library, a standard data source available in all SAS installations.

1 Code Block

PROC TEMPLATE

Explanation :
This block defines a reusable `STATGRAPH` template named `simpleStats`. It specifies the visual elements of the graph, including a title, an overlay layout to combine graphic elements, a scatter plot (`scatterPlot`) grouped by the `type` variable, and reference lines (`referenceLine`) dynamically calculated using statistical functions (`median`, `mean`, `std`) and the `eval` function. A discrete legend is added, as well as a footnote (`entryFootnote`) that displays summarized statistics (min and max of `weight`) from the data set being rendered. This template encapsulates the graph's presentation logic without processing the data at this stage, making it reusable.

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1	PROC TEMPLATE;
2	define statgraph simpleStats;
3	beginGraph;
4	entryTitle "Simple Statistics using Expression";
5	layout overlay;
6	scatterPlot x=msrp y=mpg_highway / name="sp1"
7	group=type dataTransparency=0.2;
8	referenceLine x=eval(median(msrp)) / lineAttrs=(pattern=shortDash)
9	curveLabel="x(ESC){unicode '0303'x}" curveLabelAttrs=(size=12);
10	referenceLine y=eval(mean(mpg_highway) + std(mpg_highway)) /
11	curveLabel="x(ESC){unicode '0304'x} + (ESC){unicode sigma}"
12	curveLabelAttrs=(size=12) lineAttrs=(pattern=dashDashDot);
13	referenceLine y=eval(mean(mpg_highway) - std(mpg_highway)) /
14	curveLabel="x(ESC){unicode '0304'x} - (ESC){unicode sigma}"
15	curveLabelAttrs=(size=12) lineAttrs=(pattern=dashDashDot);
16	discreteLegend "sp1" / across=3 location=inside hAlign=right vAlign=top;
17	endLayout;
18	entryFootnote halign=left "Weight (in lbs) ranges from " eval(min(weight))
19	" to " eval(max(weight)) ;
20	endGraph;
21	END;
22	RUN;

2 Code Block

PROC SGRENDER

Explanation :
This code block begins by resetting ODS graphics options (`ods graphics / reset;`) to ensure a clean graphics environment and avoid interference with previous settings. Then, the `PROC SGRENDER` procedure is used to generate the graph. It applies the `simpleStats` template previously defined (via `template=simpleStats`) to the data contained in the `sashelp.cars` table (via `data=sashelp.cars`). This produces the graph image with all the elements specified in the template, using the `msrp`, `mpg_highway`, `type`, and `weight` variables from the `cars` table for the final rendering.

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1	ods graphics / reset;
2	PROC SGRENDER
3	DATA=sashelp.cars template=simpleStats;
4	RUN;
5

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