BOXP
Prints boxplots for one or more samples.
Required Arguments
NI — Vector of length NGROUP. (Input)
NI(I) is the number of observations in the I‑th group.
X —Vector of length NI(1) + NI(2) + … + NI(NGROUP). (Input)
The first NI(1) positions contain the observations for the first group. The next NI(2) positions contain the observations for the second group, and so on.
TITLE — CHARACTER string containing the title of the plot. (Input)
Optional Arguments
NGROUP — The total number of groups of samples. (Input)
Default: NGROUP = size (NI,1).
FORTRAN 90 Interface
Generic: CALL BOXP (NI, X, TITLE [, …])
Specific: The specific interface names are S_BOXP and D_BOXP.
FORTRAN 77 Interface
Single: CALL BOXP (NGROUP, NI, X, TITLE)
Double: The double precision name is DBOXP.
Description
BOXP prints NGROUP boxplots. The minimum and maximum of X are printed. The median of each data group is marked by “*” and the upper and lower hinges by “I”. The “H‑spread” is the distance between the upper and lower hinges. The observation farthest from the median that still remains within one step (1.5 H‑spread) from each hinge also is marked by “+”. The values in the second step (between 1.5 and 3 H‑spreads from the hinges) are marked by the letter “O” and the values beyond the second step are marked by “X”. If there are fewer than five data points, each data point is plotted with an “X.” If multiple data points occur at positions marked “X” or “O”, the number of multiple points is noted. More information on boxplots can be found in Chapter 2 of Chambers et al. (1983).
Comments
1. Workspace may be explicitly provided, if desired, by use of B2XP/DB2XP. The reference is:
CALL B2XP (NGROUP, NI, X, TITLE, WKSP)
The additional argument is:
WKSP — Workspace of length NI(1) + … + NI(NGROUP). (Input)
The first NI(1) positions contain the sorted data from the first NI(1) positions of X. The next NI(2) positions contain sorted data from the next NI(2) positions of X, and so on.
2. Informational error
Type | Code | Description |
|---|
3 | 5 | TITLE is too long to fit into the page width determined by the routine PGOPT. TITLE is truncated from the right side. |
3.
TITLE is centered and placed at the top of the plot. The plot starts on a new page and the default page width is 78. The user may change the width by calling the routine
PGOPT (see
Chapter 19, "Utilities") in advance.
Example
This example prints boxplots of three batches of data containing 5, 16 and 7 observations, respectively.
USE PGOPT_INT
USE BOXP_INT
IMPLICIT NONE
INTEGER IPAGE, NGROUP, I
PARAMETER (NGROUP=3)
!
INTEGER NI(NGROUP)
REAL X(28)
!
DATA (NI(I),I=1,3)/5, 16, 7/
DATA (X(I),I=1,5)/7., 9., 3., 1., 1./
DATA (X(I),I=6,21)/25., 0., 1., 0., 5., 4., 3., 5., 5., 5., 5., &
5., 5., 25., 15., 9./
DATA (X(I),I=22,28)/10., 15., 20., 25., 2., 9., 12./
! Set page width.
IPAGE = 70
CALL PGOPT (-1, IPAGE)
CALL BOXP (NI, X, 'Plot of BOXP')
!
END
Output
Plot of BOXP
X X X X
2
I--------I
+--------I * I-----+ O X
I--------I 2
I--------------------I
+-------------------I * I-------------------+
I--------------------I
+................................+.................................+
0.0 12.5 25.0
