perlman@wanginst.UUCP (Gary Perlman) (08/12/85)
This seems to have had problems getting through before.
It was advertised in net.math.stat.
sample is an educational program for teaching about sampling distributions.
It lets you provide a distribution from which it will graphically display
the means of samples of sizes of your choice.
Posted to net.sources is the source code for sample and a mildly instructive
manual entry. I think the program might be useful for an introductory
statistics course lab demonstration. A demonstration shell script,
with some example distributions, are also included.
As part of the distribution, I have included my tiny curses package.
It looks like curses, but it's not. The nature of the sample display
requires something without screen optimization, which gets in the way here.
Tiny curses is pretty useful for screen handling without much redrawing
or the need to keep track of what is on the screen. As a demonstration
of its compatibility with real curses, you can compile sample with
regular curses and compare the running times.
Gary Perlman Wang Institute Tyngsboro, MA 01879 (617) 649-9731
UUCP: decvax!wanginst!perlman CSNET: perlman@wanginst
#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create the files:
# sample.c
# getword.c
# tc.c
# getopt.c
# makefile
# curses.h
# sample.1
# tc.3
# sample.demo
# dist.tri
# dist.antitri
# dist.skew
# dist.uni
# This archive created: Mon Aug 12 01:34:20 1985
# By: Gary Perlman (Wang Institute, Tyngsboro, MA 01879 USA)
export PATH; PATH=/bin:/usr/bin:$PATH
echo shar: "extracting 'sample.c'" '(4941 characters)'
if test -f 'sample.c'
then
echo shar: "will not over-write existing file 'sample.c'"
else
sed 's/^ X//' << \SHAR_EOF > 'sample.c'
X/*
X sample: display random samples
X*/
X#include "curses.h"
X#include <math.h>
X
Xint BOTTOM; /* set to LINES-1 */
X
X#define MAXCOLS 100 /* max # of columns on screen */
Xint Colcount[MAXCOLS]; /* current count in column bin */
Xint Sampsize = 1; /* sample size */
Xint Outline = 0; /* only show shape of distribution */
Xint Plotchar = '*'; /* histogram plotting character */
X
Xtypedef double DATUM;
X#define MAXDISTRIB 1000 /* max size of population distribution */
XDATUM Distrib[MAXDISTRIB]; /* population distribution */
Xint N = 0; /* population size */
XDATUM S1 = 0.0; /* sum of distribution values */
XDATUM S2 = 0.0; /* sum of squared distribution values */
XDATUM S3 = 0.0; /* sum of cubed distribution values */
XDATUM S4 = 0.0; /* sum of quarted distribution values */
XDATUM Max; /* distribution maximum */
XDATUM Min; /* distribution minimum */
X
Xdouble sample ();
X#define EPSILON .000000001
X#define scale(x) (((x)-Min)/(Max-Min+EPSILON)) /* in [0, 1) */
X#define fzero(x) (fabs(x) < EPSILON)
X
Xmain (argc, argv) char **argv;
X {
X double x;
X double x2;
X int n = 0;
X double s1 = 0.0;
X double s2 = 0.0;
X double s3 = 0.0;
X double s4 = 0.0;
X readdata ();
X initial (argc, argv);
X for (;;)
X {
X if (Sampsize < 1) /* just dump out distribution */
X {
X if (n == N) finish ();
X x = Distrib[n];
X }
X else x = sample (Sampsize, Distrib, N);
X x2 = x * x;
X n++;
X s1 += x;
X s2 += x2;
X s3 += x2 * x;
X s4 += x2 * x2;
X if (plotdata (x, n, s1, s2, s3, s4) == 0)
X if (Sampsize > 0) finish ();
X else beep ();
X }
X }
X
Xreaddata ()
X {
X DATUM x;
X DATUM x2;
X char string[100];
X while (getword (string, stdin))
X {
X if (N == MAXDISTRIB)
X {
X fprintf (stderr, "sample: max # of values = %d\n", MAXDISTRIB);
X exit (1);
X }
X x = atof (string);
X if (N == 0) /* first time around */
X Min = Max = x;
X else if (x > Max)
X Max = x;
X else if (x < Min)
X Min = x;
X Distrib[N++] = x;
X S1 += x;
X x2 = x * x;
X S2 += x2;
X S3 += x2 * x;
X S4 += x2 * x2;
X }
X if (N == 0)
X {
X fprintf (stderr, "sample: missing input distribution\n");
X exit (2);
X }
X }
X
Xinitial (argc, argv) char **argv;
X {
X long time ();
X extern char *optarg;
X extern int optind;
X int errflg = 0;
X int C;
X char *optstring = "c:n:o";
X char *usage = "[-o] [-c plotchar] [-n size]";
X while ((C = getopt (argc, argv, optstring)) != EOF)
X switch (C)
X {
X case 'c': Plotchar = *optarg; break;
X case 'n': Sampsize = atoi (optarg); break;
X case 'o': Outline = 1; break;
X default: errflg++; break;
X }
X if (errflg)
X {
X fprintf (stderr, "Usage: %s %s\n", argv[0], usage);
X exit (1);
X }
X srandom (time (0) + getpid ());
X initscr ();
X BOTTOM = LINES-1;
X clear ();
X bottomline ();
X inform (0, N, S1, S2, S3, S4);
X refresh ();
X }
X
Xbottomline ()
X {
X char buf[BUFSIZ];
X int width = 7;
X move (BOTTOM, 0);
X clrtoeol ();
X standout ();
X printw ("%-.2f", Min);
X move (BOTTOM, COLS-width);
X printw ("%*.2f", width-1, Max);
X if (Sampsize > 0)
X sprintf (buf, "Displaying samples of size %d", Sampsize);
X else
X sprintf (buf, "Displaying the base distribution");
X move (BOTTOM, (COLS-strlen(buf))/2);
X printw (buf);
X standend ();
X }
X
Xfinish ()
X {
X move (BOTTOM, 0);
X clrtoeol ();
X refresh ();
X endwin ();
X exit (0);
X }
X
X/*
X takes a sample of size "n" from a supplied vector
X returns the mean of the sample
X*/
Xdouble
Xsample (n, distrib, size)
Xint n; /* sample size */
XDATUM *distrib; /* vector of population values */
Xint size; /* size of population distribution */
X {
X int trial;
X DATUM s1 = 0.0;
X if (n == 0 || size == 0) return (0.0);
X for (trial = 0; trial < n; trial++)
X s1 += distrib [ random () % size ];
X return (s1 / n);
X }
X
Xplotdata (x, n, s1, s2, s3, s4)
Xdouble x;
Xint n;
Xdouble s1;
Xdouble s2;
Xdouble s3;
Xdouble s4;
X {
X int dindex = (int) (scale (x) * COLS);
X int col = dindex;
X int row;
X Colcount[dindex]++;
X if (Colcount[dindex] < BOTTOM)
X {
X inform (40, n, s1, s2, s3, s4);
X row = LINES-Colcount[dindex]-1;
X if (Outline && row < BOTTOM-1)
X {
X move (row+1, col);
X addch (' ');
X }
X move (row, col);
X addch (Plotchar);
X refresh ();
X return (1);
X }
X else return (0);
X }
X
Xinform (column, n, s1, s2, s3, s4)
Xint column;
Xint n;
Xdouble s1;
Xdouble s2;
Xdouble s3;
Xdouble s4;
X {
X double M = 0.0;
X double var = 0.0;
X double sd = 0.0;
X double skew;
X double kurtosis;
X double m2;
X if (n > 0)
X {
X move (0, column);
X M = s1/n;
X printw ("#%-4d %5.2f ", n, M);
X m2 = M * M;
X if (n > 1)
X {
X var = (s2 - M*s1)/(n-1);
X if (fzero (var)) kurtosis = skew = sd = var = 0.0;
X else
X {
X sd = sqrt (var);
X skew = (s3 - 3.0*M*s2 + 3.0*m2*s1 - m2*s1)/(n*var*sd);
X kurtosis = (s4-4.*M*s3+6.*m2*s2-4.*m2*M*s1+n*m2*m2)/(n*var*var);
X }
X printw (" %5.2f", sd);
X printw (" %5.2f", skew);
X printw (" %5.2f", kurtosis);
X clrtoeol ();
X }
X }
X }
SHAR_EOF
if test 4941 -ne "`wc -c < 'sample.c'`"
then
echo shar: "error transmitting 'sample.c'" '(should have been 4941 characters)'
fi
fi
echo shar: "extracting 'getword.c'" '(631 characters)'
if test -f 'getword.c'
then
echo shar: "will not over-write existing file 'getword.c'"
else
sed 's/^ X//' << \SHAR_EOF > 'getword.c'
X/* LINTLIBRARY */
X#include <stdio.h>
X#include <ctype.h>
X/*
X getword(string,ioptr) is equivalent to fscanf(ioptr,"%s",string)
X but much faster. It returns a NULL pointer on EOF or the end
X of the string when one is found. The return result can be used
X to find the length of the obtained string.
X*/
X
Xchar *
Xgetword (string, ioptr)
Xregister char *string;
Xregister FILE *ioptr;
X {
X register int C;
X while ((C = getc (ioptr)) != EOF && isspace (C));
X if (C == EOF) return (NULL);
X do
X {
X *string++ = C;
X } while ((C = getc (ioptr)) != EOF && !isspace (C));
X *string = '\0';
X return (string); /* pointer to the end of string */
X }
SHAR_EOF
if test 631 -ne "`wc -c < 'getword.c'`"
then
echo shar: "error transmitting 'getword.c'" '(should have been 631 characters)'
fi
fi
echo shar: "extracting 'tc.c'" '(5913 characters)'
if test -f 'tc.c'
then
echo shar: "will not over-write existing file 'tc.c'"
else
sed 's/^ X//' << \SHAR_EOF > 'tc.c'
X/* LINTLIBRARY */
X/*
X These are simple versions of the curses(3) screen handling functions.
X Tiny curses does not support windows or screen optimization,
X so they are simply a high level interface to the termcap(3) functions.
X*/
X
Xstatic char sccsid[] = "@(#) Tiny_Curses 1.0 (WangInst) Feb 24 85";
X#include "curses.h"
X
X#include <sgtty.h>
Xstatic struct sgttyb Savetty; /* save tty state here */
Xstatic struct sgttyb Curtty; /* current tty state here */
X
X#include <signal.h>
X
Xextern char *getenv ();
Xextern char *tgetstr ();
Xextern char *tgoto ();
X
Xstatic
Xint
Xoutchar (c) /* static fun used to output characters by termcap */
Xregister int c;
X {
X putc (c, stdout);
X }
X
Xint LINES; /* number of lines */
Xint COLS; /* number of columns */
X
X/* these external variables are used by termcap functions */
Xchar PC; /* padding character */
Xchar *BC; /* backspace */
Xchar *UP; /* up */
Xshort ospeed; /* output speed */
X
X/* terminal capabilities strings stored for efficiency */
Xstatic char *CD; /* clear to end of display */
Xstatic char *CE; /* clear to end of line */
Xstatic char *CL; /* clear line */
Xstatic char *AL; /* add (insert) line */
Xstatic char *DL; /* delete line */
Xstatic char *CM; /* cursor movement */
Xstatic char *VB; /* visible bell */
Xstatic char *SO; /* stand out */
Xstatic char *SE; /* stand end */
Xstatic char *IC; /* insert char */
Xstatic char *IM; /* enter insert char mode */
Xstatic char *EI; /* end insert mode */
Xstatic char *DC; /* delete char */
Xstatic char *DM; /* enter delete char mode */
Xstatic char *ED; /* end delete mode */
Xstatic char *US; /* underscore */
Xstatic char *UE; /* underend */
X
X/*FUN .FN void refresh () "flush output to screen */
Xvoid
Xrefresh ()
X {
X (void) fflush (stdout);
X }
X
X/*FUN .FN void setterm "(char *name)" "set terminal capabilities */
Xvoid
Xsetterm (name)
Xchar *name;
X {
X char Termcap[1024]; /* termcap entry stored here */
X static char Abuf[BUFSIZ]; /* capabilities stored here */
X char *area = Abuf;
X char *ptr;
X if (name == NULL) return;
X if (tgetent (Termcap, name) != 1) return;
X BC = tgetstr ("bc", &area);
X ptr = tgetstr ("pc", &area);
X if (ptr && *ptr) PC = *ptr;
X UP = tgetstr ("up", &area);
X COLS = tgetnum ("co");
X LINES = tgetnum ("li");
X AL = tgetstr ("al", &area);
X CD = tgetstr ("cd", &area);
X CE = tgetstr ("ce", &area);
X CL = tgetstr ("cl", &area);
X CM = tgetstr ("cm", &area);
X DC = tgetstr ("dc", &area);
X DL = tgetstr ("dl", &area);
X DM = tgetstr ("dm", &area);
X ED = tgetstr ("ed", &area);
X EI = tgetstr ("ei", &area);
X IC = tgetstr ("ic", &area);
X IM = tgetstr ("im", &area);
X SE = tgetstr ("se", &area);
X SO = tgetstr ("so", &area);
X UE = tgetstr ("ue", &area);
X US = tgetstr ("us", &area);
X VB = tgetstr ("vb", &area);
X }
X
X/*FUN .FN void crmode () "put tty in cbreak mode */
Xvoid
Xcrmode ()
X {
X Curtty.sg_flags |= CBREAK;
X (void) stty (0, &Curtty);
X }
X
X/*FUN .FN void nocrmode () "take tty out of cbreak mode */
Xnocrmode () /* out of cbreak mode */
X {
X Curtty.sg_flags &= ~CBREAK;
X (void) stty (0, &Curtty);
X }
X
X/*FUN .FN void raw () "put tty in raw mode */
Xvoid
Xraw ()
X {
X Curtty.sg_flags |= RAW;
X (void) stty (0, &Curtty);
X }
X
X/*FUN .FN void noraw () "take tty out of raw mode */
Xvoid
Xnoraw ()
X {
X Curtty.sg_flags &= ~RAW;
X (void) stty (0, &Curtty);
X }
X
X/*FUN .FN void echo () "have tty echo input characters */
Xvoid
Xecho ()
X {
X Curtty.sg_flags |= ECHO;
X (void) stty (0, &Curtty);
X }
X
X/*FUN .FN void noecho () "have tty echo not input characters */
Xvoid
Xnoecho ()
X {
X Curtty.sg_flags &= ~ECHO;
X (void) stty (0, &Curtty);
X }
X
X/*FUN .FN void resetty () "reset tty to stored state */
Xvoid
Xresetty ()
X {
X (void) stty (0, &Savetty);
X }
X
X/*FUN .FN void savetty () "save tty state */
Xvoid
Xsavetty ()
X {
X (void) gtty (0, &Savetty);
X }
X
X/*FUN .FN void standout () "begin highlighted text */
Xvoid
Xstandout ()
X {
X tputs (SO, 1, outchar);
X }
X
X/*FUN .FN void standend () "end highlighted text */
Xvoid
Xstandend ()
X {
X tputs (SE, 1, outchar);
X }
X
X/*FUN .FN void underscore () "begin underscored text */
Xvoid
Xunderscore ()
X {
X tputs (US, 1, outchar);
X }
X
X/*FUN .FN void underend () "end underscored text */
Xunderend ()
X {
X tputs (UE, 1, outchar);
X }
X
X/*FUN .FN void beep () "visible bell or at least beep */
Xvoid
Xbeep ()
X {
X if (VB && *VB)
X tputs (VB, 1, outchar);
X else outchar ('\007');
X }
X
X/*FUN .FN void clear () "clear screen */
Xvoid
Xclear ()
X {
X tputs (CL, LINES, outchar);
X }
X
X/*FUN .FN void clrtoeol () "clear to end of line */
Xvoid
Xclrtoeol ()
X {
X tputs (CE, 1, outchar);
X }
X
X/*FUN .FN void clrtobot () "clear to bottom of screen */
Xvoid
Xclrtobot ()
X {
X tputs (CD, LINES, outchar);
X }
X
X/*FUN .FN void delch () "delete the character under the cursor */
Xvoid
Xdelch ()
X {
X tputs (DM, 1, outchar);
X tputs (DC, 1, outchar);
X tputs (ED, 1, outchar);
X }
X
X/*FUN .FN void deleteln () "delete the current line */
Xvoid
Xdeleteln ()
X {
X tputs (DL, LINES, outchar);
X }
X
X/*FUN .FN void insch "(int c)" "insert character */
Xvoid
Xinsch (c)
Xint c;
X {
X tputs (IM, 1, outchar);
X tputs (IC, 1, outchar);
X outchar (c);
X tputs (EI, 1, outchar);
X }
X
X/*FUN .FN void insertln () "insert line */
Xvoid
Xinsertln ()
X {
X tputs (AL, LINES, outchar);
X }
X
X/*FUN .FN void move "(int y, x)" "move to line=y col=x (zero origin) */
Xvoid
Xmove (y, x)
Xregister int y;
Xregister int x;
X {
X if (y < 0 || x < 0) return;
X if (y >= LINES || x >= COLS) return;
X tputs (tgoto(CM,x,y), 1, outchar);
X }
X
X/*FUN .FN void endwin () "reset tty to old parameters */
Xvoid
Xendwin ()
X {
X (void) resetty ();
X }
X
Xstatic
Xdie () /* static function used to die gracefully */
X {
X (void) signal (SIGINT, SIG_IGN);
X beep ();
X move (LINES-1, 0);
X clrtoeol ();
X endwin ();
X exit (1);
X }
X
X/*FUN .FN void initscr () "initialize screen */
Xvoid
Xinitscr ()
X {
X extern die ();
X (void) savetty ();
X (void) gtty (0, &Curtty);
X Curtty.sg_flags &= ~XTABS;
X (void) stty (0, &Curtty);
X ospeed = Savetty.sg_ospeed;
X (void) setterm (getenv ("TERM"));
X (void) signal (SIGINT, die);
X }
SHAR_EOF
if test 5913 -ne "`wc -c < 'tc.c'`"
then
echo shar: "error transmitting 'tc.c'" '(should have been 5913 characters)'
fi
fi
echo shar: "extracting 'getopt.c'" '(2961 characters)'
if test -f 'getopt.c'
then
echo shar: "will not over-write existing file 'getopt.c'"
else
sed 's/^ X//' << \SHAR_EOF > 'getopt.c'
X/*
X I got this off net.sources from Henry Spencer.
X It is a public domain getopt(3) like in SYstem V.
X I have made the following modifications:
X
X index(s,c) was added because too many people could
X not compile getopt without it.
X
X A test main program was added, ifdeffed by STANDALONE.
X This main program is a public domain implementation
X of the getopt(1) program like in System V. The getopt
X program can be used to standardize shell option handling.
X e.g. cc -DSTANDALONE getopt.c -o getopt
X*/
X#include <stdio.h>
Xstatic char sccsfid[] = "@(#) getopt.c 5.0 (UTZoo) 1985";
X
X#define ARGCH (int)':'
X#define BADCH (int)'?'
X#define EMSG ""
X#define ENDARGS "--"
X
X/* this is included because index is not on some UNIX systems */
Xstatic
Xchar *
Xindex (s, c)
Xregister char *s;
Xregister int c;
X {
X while (*s)
X if (c == *s) return (s);
X else s++;
X return (NULL);
X }
X
X/*
X * get option letter from argument vector
X */
Xint opterr = 1, /* useless, never set or used */
X optind = 1, /* index into parent argv vector */
X optopt; /* character checked for validity */
Xchar *optarg; /* argument associated with option */
X
X#define tell(s) fputs(*nargv,stderr);fputs(s,stderr); \
X fputc(optopt,stderr);fputc('\n',stderr);return(BADCH);
X
Xgetopt(nargc,nargv,ostr)
Xint nargc;
Xchar **nargv,
X *ostr;
X{
X static char *place = EMSG; /* option letter processing */
X register char *oli; /* option letter list index */
X char *index();
X
X if(!*place) { /* update scanning pointer */
X if(optind >= nargc || *(place = nargv[optind]) != '-' || !*++place) return(EOF);
X if (*place == '-') { /* found "--" */
X ++optind;
X return(EOF);
X }
X } /* option letter okay? */
X if ((optopt = (int)*place++) == ARGCH || !(oli = index(ostr,optopt))) {
X if(!*place) ++optind;
X tell(": illegal option -- ");
X }
X if (*++oli != ARGCH) { /* don't need argument */
X optarg = NULL;
X if (!*place) ++optind;
X }
X else { /* need an argument */
X if (*place) optarg = place; /* no white space */
X else if (nargc <= ++optind) { /* no arg */
X place = EMSG;
X tell(": option requires an argument -- ");
X }
X else optarg = nargv[optind]; /* white space */
X place = EMSG;
X ++optind;
X }
X return(optopt); /* dump back option letter */
X}
X
X#ifdef STANDALONE
Xstatic char sccspid[] = "@(#) getopt.c 5.1 (WangInst) 6/15/85";
Xmain (argc, argv) char **argv;
X {
X char *optstring = argv[1];
X char *argv0 = argv[0];
X extern int optind;
X extern char *optarg;
X int opterr = 0;
X int C;
X char *opi;
X if (argc == 1)
X {
X fprintf (stderr, "Usage: %s optstring args\n", argv0);
X exit (1);
X }
X argv++;
X argc--;
X argv[0] = argv0;
X while ((C = getopt (argc, argv, optstring)) != EOF)
X {
X if (C == BADCH) opterr++;
X printf ("-%c ", C);
X opi = index (optstring, C);
X if (opi && opi[1] == ARGCH)
X if (optarg)
X printf ("\"%s\" ", optarg);
X else opterr++;
X }
X printf ("%s", ENDARGS);
X while (optind < argc)
X printf (" \"%s\"", argv[optind++]);
X putchar ('\n');
X exit (opterr);
X }
X
X#endif
SHAR_EOF
if test 2961 -ne "`wc -c < 'getopt.c'`"
then
echo shar: "error transmitting 'getopt.c'" '(should have been 2961 characters)'
fi
fi
echo shar: "extracting 'makefile'" '(669 characters)'
if test -f 'makefile'
then
echo shar: "will not over-write existing file 'makefile'"
else
sed 's/^ X//' << \SHAR_EOF > 'makefile'
X# NB if your system does not have the functions: random and srandom,
X#then un-comment the next line
X#DEFS=-Drandom=rand -Dsrandom=srand
X
X# NB if your system has getopt, then remove all references to getopt here
XSRCS=sample.c getword.c tc.c getopt.c
XOBJS=sample.o getword.o tc.o getopt.o
X
XDOCS=sample.1 tc.3
XHDRS=curses.h
XDEMO=sample.demo dist.tri dist.antitri dist.skew dist.uni
XARCS=$(SRCS) makefile $(DIST) $(HDRS) $(DOCS) $(DEMO)
XLIBS=-ltermlib -lm
XCFLAGS=-O
X
Xsample: $(OBJS)
X cc $(CFLAGS) -o sample $(OBJS) $(LIBS)
X
Xsample.o: sample.c
X cc $(CFLAGS) -c $(DEFS) sample.c
X
Xdemo: sample
X sample.demo
X
Xarchive: $(ARCS)
X shar -a $(ARCS) > archive
X
Xlint:
X lint -h $(SRCS)
SHAR_EOF
if test 669 -ne "`wc -c < 'makefile'`"
then
echo shar: "error transmitting 'makefile'" '(should have been 669 characters)'
fi
fi
echo shar: "extracting 'curses.h'" '(305 characters)'
if test -f 'curses.h'
then
echo shar: "will not over-write existing file 'curses.h'"
else
sed 's/^ X//' << \SHAR_EOF > 'curses.h'
X#ifndef TC_H
X
X#include <stdio.h>
X
X#define addch(c) putchar(c)
X#define addstr(s) fputs(s, stdout)
X#define printw printf
X#define getch() getchar()
X#define getstr(s) gets(s)
X
Xextern int LINES; /* number of lines in display */
Xextern int COLS; /* number of columns in display */
X
X#define TC_H
X#endif
SHAR_EOF
if test 305 -ne "`wc -c < 'curses.h'`"
then
echo shar: "error transmitting 'curses.h'" '(should have been 305 characters)'
fi
fi
echo shar: "extracting 'sample.1'" '(2284 characters)'
if test -f 'sample.1'
then
echo shar: "will not over-write existing file 'sample.1'"
else
sed 's/^ X//' << \SHAR_EOF > 'sample.1'
X.TH SAMPLE 1WI "10 May 1985" "Wang Institute" "UNIX User's Manual"
X.SH NAME
Xsample \- take random samples from a statistical distribution
X.SH SYNOPSIS
X.B sample
X[-c plotchar] [-n size] [-o]
X.SH OPTIONS
X.de OP
X.TP
X.B -\\$1 \\$2
X..
X.OP c plotchar
Xset the histogram plotting character.
X.OP n size
Xset the sample size.
XIf the sample size is less than or equal to zero,
Xthen the input distribution is displayed.
X.OP o
Xshow only the outline of the distribution.
XThis ends up looking like a race one might want to place bets on.
X.SH DESCRIPTION
X.PP
X.I sample
Xcan help develop intuitions about how statistics of samples from distributions
Xare related to the distributions.
X.I sample
Xreads in a distribution of whitespace separated numbers from the standard input
Xand randomly samples from that distribution,
Xshowing statistics and a dynamic histogram of the sample means.
X.SS "The Display
X.PP
XOn the top line of the display are
Xstatistics about the parent distribution and the sampling
Xdistribution of the mean of the specified sized samples.
XThe statistics include:
Xthe size, (grand) mean, standard deviation, skew, and kurtosis.
XThe histogram of the sample means
Xscales the values to fit in the width of the screen
Xand grows until the screen would overflow.
X.SS "Things to Watch For
X.PP
XThe expected value of the standard deviation of
Xthe sampling distribution of the mean
X(often called the standard error of the mean, or SE)
Xis:
X.ce
XSE = SD / sqrt(N)
Xwhere SD is the standard deviation of the parent distribution
Xfrom which samples are being taken,
Xand N is the sample size.
XSo, if samples of size 25 are taken,
Xthen the expected value of the standard error is one fifth
Xof the standard deviation of the parent distribution.
XThe expected value of the sample means (the mean of the means)
Xis the mean of the parent distribution.
X.PP
XFor reference,
Xnormal distributions have zero skew and kurtosis equal to 3.0.
XIt is instructive to see that for any shaped parent distribution,
Xthe sampling distribution of the mean approaches a normal distribution
Xas the sample size increases.
XThis is proven in the central limit theorem.
X.SH EXAMPLE
X.PP
XThe following takes samples of size 100 from the distribution
Xof numbers 1-10.
X.ce
Xecho "1 2 3 4 5 6 7 8 9 10" | sample -n 100
X.SH AUTHOR
XGary Perlman
SHAR_EOF
if test 2284 -ne "`wc -c < 'sample.1'`"
then
echo shar: "error transmitting 'sample.1'" '(should have been 2284 characters)'
fi
fi
echo shar: "extracting 'tc.3'" '(2597 characters)'
if test -f 'tc.3'
then
echo shar: "will not over-write existing file 'tc.3'"
else
sed 's/^ X//' << \SHAR_EOF > 'tc.3'
X.TH TC(3WI)
X.SH NAME
Xtiny curses \- screen functions without ``optimal'' cursor motion
X.SH SYNOPSIS
Xcc [flags] files tc.o -ltermlib [libraries]
X.SH DESCRIPTION
XThese routines give the programmer the high level
Xcurses(3) interface to the termcap(3) functions
Xwithout the overhead of the curses(3) screen optimization capabilities.
XTiny curses is useful for simple screen formatting
Xand is more efficient for displays that do not require
Xsignificant redrawing.
X.PP
XTo use the routines,
Xthe function
X.I initscr()
Xshould be called before any others.
XThe routine
X.I endwin()
Xshould be called before exiting.
X.PP
XThe names of the functions are identical to those of curses(3)
Xso that it is easy to move from Tiny curses to real curses(3).
XThere are many functions provided by curses(3) that are not provided
Xhere (e.g., windows), so the opposite translation is more difficult.
X.SH AUTHOR
XGary Perlman
X.SH "SEE ALSO
Xcurses(3), termcap(3), termcap(5)
X.SH FILES
X.nf
X.ta 1.5i
X#include "curses.h" definitions of variables and compatibility functions
X/etc/termcap terminal capability database
X.SH VARIABLES
X.nf
X.ta 1i
Xint LINES; /* number of lines in display */
Xint COLS; /* number of columns in display */
X.SH FUNCTIONS
X.SS "Basic
X.nf
X.ta 1i
Xendwin () reset tty to old parameters
Xinitscr () initialize screen
Xmove (y, x) move to line=y column=x (zero origin)
Xrefresh () flush output to screen (fflush(stdout))
X.SS "Clear Regions
X.nf
X.ta 1i
Xclear () clear screen
Xclrtobot () clear to bottom of screen
Xclrtoeol () clear to end of line
X.SS "Terminal Functions
X.nf
X.ta 1i
Xcrmode () cbreak mode
Xecho () echo characters
Xnocrmode () out of cbreak mode
Xnoecho () don't echo characters
Xnoraw () no raw mode
Xraw () raw mode
Xresetty () reset tty to stored state
Xsavetty () save tty state
X.SS Highlighting
X.nf
X.ta 1i
Xbeep () visible or at least audible bell
Xstandend () don't highlight text
Xstandout () highlight text
Xunderend () end underscore mode
Xunderscore () underscore characters
X.SS "Editing Functions
X.nf
X.ta 1i
Xdelch () delete the character under the cursor
Xdeleteln () delete the current line
Xinsch (c) insert character
Xinsertln () insert line
X.SH DIAGNOSTICS
X.PP
XTo be compatible with curses(3),
Xthere are no diagnostics.
X.SH NOTES
X.PP
XThe refresh() function is actually a call to fflush(stdout)
Xto flush the output buffer.
XThus, the tiny curses refresh() may be used
Xto guarantee that some text is on the screen,
Xbut it might go out sooner.
X.PP
XTiny curses assumes you want to catch interrupts,
Xso initscr() sets things up so that an interrupt
Xwill reset the tty, move to the bottom of the screen,
Xand exit.
SHAR_EOF
if test 2597 -ne "`wc -c < 'tc.3'`"
then
echo shar: "error transmitting 'tc.3'" '(should have been 2597 characters)'
fi
fi
echo shar: "extracting 'sample.demo'" '(240 characters)'
if test -f 'sample.demo'
then
echo shar: "will not over-write existing file 'sample.demo'"
else
sed 's/^ X//' << \SHAR_EOF > 'sample.demo'
X#! /bin/sh
Xfor distribution in dist.skew dist.uni dist.tri dist.antitri
Xdo
X for size in 0 1 4 25
X do
X /bin/echo -n "Type RETURN to see samples of size $size from $distribution: "
X read junk
X sample $* -n $size < $distribution
X done
Xdone
SHAR_EOF
if test 240 -ne "`wc -c < 'sample.demo'`"
then
echo shar: "error transmitting 'sample.demo'" '(should have been 240 characters)'
fi
chmod +x 'sample.demo'
fi
echo shar: "extracting 'dist.tri'" '(255 characters)'
if test -f 'dist.tri'
then
echo shar: "will not over-write existing file 'dist.tri'"
else
sed 's/^ X//' << \SHAR_EOF > 'dist.tri'
X1
X2 2
X3 3 3
X4 4 4 4
X5 5 5 5 5
X6 6 6 6 6 6
X7 7 7 7 7 7 7
X8 8 8 8 8 8 8 8
X9 9 9 9 9 9 9 9 9
X10 10 10 10 10 10 10 10 10 10
X11 11 11 11 11 11 11 11 11
X12 12 12 12 12 12 12 12
X13 13 13 13 13 13 13
X14 14 14 14 14 14
X15 15 15 15 15
X16 16 16 16
X17 17 17
X18 18
X19
SHAR_EOF
if test 255 -ne "`wc -c < 'dist.tri'`"
then
echo shar: "error transmitting 'dist.tri'" '(should have been 255 characters)'
fi
fi
echo shar: "extracting 'dist.antitri'" '(274 characters)'
if test -f 'dist.antitri'
then
echo shar: "will not over-write existing file 'dist.antitri'"
else
sed 's/^ X//' << \SHAR_EOF > 'dist.antitri'
X1 1 1 1 1 1 1 1 1 1
X2 2 2 2 2 2 2 2 2
X3 3 3 3 3 3 3 3
X4 4 4 4 4 4 4
X5 5 5 5 5 5
X6 6 6 6 6
X7 7 7 7
X8 8 8
X9 9
X10
X11 11
X12 12 12
X13 13 13 13
X14 14 14 14 14
X15 15 15 15 15 15
X16 16 16 16 16 16 16
X17 17 17 17 17 17 17 17
X18 18 18 18 18 18 18 18 18
X19 19 19 19 19 19 19 19 19 19
X
SHAR_EOF
if test 274 -ne "`wc -c < 'dist.antitri'`"
then
echo shar: "error transmitting 'dist.antitri'" '(should have been 274 characters)'
fi
fi
echo shar: "extracting 'dist.skew'" '(2363 characters)'
if test -f 'dist.skew'
then
echo shar: "will not over-write existing file 'dist.skew'"
else
sed 's/^ X//' << \SHAR_EOF > 'dist.skew'
X
X0
X0.693147
X1.09861
X1.38629
X1.60944
X1.79176
X1.94591
X2.07944
X2.19722
X2.30259
X2.3979
X2.48491
X2.56495
X2.63906
X2.70805
X2.77259
X2.83321
X2.89037
X2.94444
X2.99573
X3.04452
X3.09104
X3.13549
X3.17805
X3.21888
X3.2581
X3.29584
X3.3322
X3.3673
X3.4012
X3.43399
X3.46574
X3.49651
X3.52636
X3.55535
X3.58352
X3.61092
X3.63759
X3.66356
X3.68888
X3.71357
X3.73767
X3.7612
X3.78419
X3.80666
X3.82864
X3.85015
X3.8712
X3.89182
X3.91202
X3.93183
X3.95124
X3.97029
X3.98898
X4.00733
X4.02535
X4.04305
X4.06044
X4.07754
X4.09434
X4.11087
X4.12713
X4.14313
X4.15888
X4.17439
X4.18965
X4.20469
X4.21951
X4.23411
X4.2485
X4.26268
X4.27667
X4.29046
X4.30407
X4.31749
X4.33073
X4.34381
X4.35671
X4.36945
X4.38203
X4.39445
X4.40672
X4.41884
X4.43082
X4.44265
X4.45435
X4.46591
X4.47734
X4.48864
X4.49981
X4.51086
X4.52179
X4.5326
X4.54329
X4.55388
X4.56435
X4.57471
X4.58497
X4.59512
X4.60517
X4.61512
X4.62497
X4.63473
X4.64439
X4.65396
X4.66344
X4.67283
X4.68213
X4.69135
X4.70048
X4.70953
X4.7185
X4.72739
X4.7362
X4.74493
X4.75359
X4.76217
X4.77068
X4.77912
X4.78749
X4.79579
X4.80402
X4.81218
X4.82028
X4.82831
X4.83628
X4.84419
X4.85203
X4.85981
X4.86753
X4.8752
X4.8828
X4.89035
X4.89784
X4.90527
X4.91265
X4.91998
X4.92725
X4.93447
X4.94164
X4.94876
X4.95583
X4.96284
X4.96981
X4.97673
X4.98361
X4.99043
X4.99721
X5.00395
X5.01064
X5.01728
X5.02388
X5.03044
X5.03695
X5.04343
X5.04986
X5.05625
X5.0626
X5.0689
X5.07517
X5.0814
X5.0876
X5.09375
X5.09987
X5.10595
X5.11199
X5.11799
X5.12396
X5.1299
X5.1358
X5.14166
X5.14749
X5.15329
X5.15906
X5.16479
X5.17048
X5.17615
X5.18178
X5.18739
X5.19296
X5.1985
X5.20401
X5.20949
X5.21494
X5.22036
X5.22575
X5.23111
X5.23644
X5.24175
X5.24702
X5.25227
X5.2575
X5.26269
X5.26786
X5.273
X5.27811
X5.2832
X5.28827
X5.2933
X5.29832
X5.3033
X5.30827
X5.31321
X5.31812
X5.32301
X5.32788
X5.33272
X5.33754
X5.34233
X5.34711
X5.35186
X5.35659
X5.36129
X5.36598
X5.37064
X5.37528
X5.3799
X5.3845
X5.38907
X5.39363
X5.39816
X5.40268
X5.40717
X5.41165
X5.4161
X5.42053
X5.42495
X5.42935
X5.43372
X5.43808
X5.44242
X5.44674
X5.45104
X5.45532
X5.45959
X5.46383
X5.46806
X5.47227
X5.47646
X5.48064
X5.4848
X5.48894
X5.49306
X5.49717
X5.50126
X5.50533
X5.50939
X5.51343
X5.51745
X5.52146
X5.52545
X5.52943
X5.53339
X5.53733
X5.54126
X5.54518
X5.54908
X5.55296
X5.55683
X5.56068
X5.56452
X5.56834
X5.57215
X5.57595
X5.57973
X5.5835
X5.58725
X5.59099
X5.59471
X5.59842
X5.60212
X5.6058
X5.60947
X5.61313
X5.61677
X5.6204
X5.62402
X5.62762
X5.63121
X5.63479
X5.63835
X5.64191
X5.64545
X5.64897
X5.65249
X5.65599
X5.65948
X5.66296
X5.66643
X5.66988
X5.67332
X5.67675
X5.68017
X5.68358
X5.68698
X5.69036
X5.69373
X5.69709
X5.70044
X5.70378
SHAR_EOF
if test 2363 -ne "`wc -c < 'dist.skew'`"
then
echo shar: "error transmitting 'dist.skew'" '(should have been 2363 characters)'
fi
fi
echo shar: "extracting 'dist.uni'" '(229 characters)'
if test -f 'dist.uni'
then
echo shar: "will not over-write existing file 'dist.uni'"
else
sed 's/^ X//' << \SHAR_EOF > 'dist.uni'
X1 2 3 4 5 6 7 8 9 10
X11 12 13 14 15 16 17 18 19 20
X21 22 23 24 25 26 27 28 29 30
X31 32 33 34 35 36 37 38 39 40
X41 42 43 44 45 46 47 48 49 50
X51 52 53 54 55 56 57 58 59 60
X61 62 63 64 65 66 67 68 69 70
X71 72 73 74 75 76 77 78 79
SHAR_EOF
if test 229 -ne "`wc -c < 'dist.uni'`"
then
echo shar: "error transmitting 'dist.uni'" '(should have been 229 characters)'
fi
fi
exit 0
# End of shell archive
--
Gary Perlman Wang Institute Tyngsboro, MA 01879 (617) 649-9731
UUCP: decvax!wanginst!perlman CSNET: perlman@wanginst