## Example 15.4 Creating Box-and-Whisker Plots with Varying Widths

[See SHWBOX7 in the SAS/QC Sample Library]This example shows how to create a box chart with box-and-whisker plots whose widths vary proportionately with the subgroup sample size. The following statements create a SAS data set named Times2 that contains flight departure delays (in minutes) recorded daily for eight consecutive days:

```data Times2;
label Delay = 'Delay in Minutes';
informat Day date7. ;
format   Day date7. ;
input Day @ ;
do Flight=1 to 25;
input Delay @ ;
output;
end;
datalines;
01MAR90   12  4   2   2  15   8   0  11   0   0
0  12   3   .   2   3   5   0   6  25
7   4   9   5  10
02MAR90   1   .   3   .   0   1   5   0   .   .
1   5   7   .   7   2   2  16   2   1
3   1  31   .   0
03MAR90   6   8   4   2   3   2   7   6  11   3
2   7   0   1  10   2   5  12   8   6
2   7   2   4   5
04MAR90  12   6   9   0  15   7   1   1   0   2
5   6   5  14   7  21   8   1  14   3
11   0   1  11   7
05MAR90   2   1   0   4   .   6   2   2   1   4
1  11   .   1   0   .   5   5   .   2
3   6   6   4   0
06MAR90   8   6   5   2   9   7   4   2   5   1
2   2   4   2   5   1   3   9   7   8
1   0   4  26  27
07MAR90   9   6   6   2   7   8   .   .  10   8
0   2   4   3   .   .   .   7   .   6
4   0   .   .   .
08MAR90   1   6   6   2   8   8   5   3   5   0
8   2   4   2   5   1   6   4   5  10
2   0   4   1   1
;
```

The following statements create the box chart shown in Output 15.4.1:

```title 'Analysis of Airline Departure Delays';
proc shewhart data=Times2;
boxchart Delay * Day /
nohlabel
boxstyle      = schematic
odstitle      = title
boxwidthscale = 1 ;
run;
```

The BOXWIDTHSCALE=1 option specifies that the widths of the box-and-whisker plots are to vary proportionately to the subgroup sample size . This option is useful in situations where the sample size varies widely across subgroups. For further details, see the entry for BOXWIDTHSCALE= in Dictionary of Options: SHEWHART Procedure.

Output 15.4.1 Box Chart with Box-and-Whisker Plots of Varying Widths