ref: 1ffdff9257f93efc812d527426e01d7785c4a90f
parent: ab4bfbbc7ec643fc678b7311b703e513ee07f6de
author: qwx <qwx@sciops.net>
date: Wed Oct 28 20:56:00 EDT 2020
add more stupid shit
--- /dev/null
+++ b/stt/arithmeticmean.t
@@ -1,0 +1,7 @@
+The arithmetic mean of a variable X is ...
+.Bp
+The arithmetic mean of a variable X is:
+
+.EQ
+X highbar = {sum from 0 to N {X sub i}} over N+.EN
--- /dev/null
+++ b/stt/db
@@ -1,0 +1,6 @@
+2.5 1 1541980172 1542066572 arithmeticmean.ms
+2.5 1 1541980172 1542066572 variance.ms
+2.5 1 1541980172 1542066572 variance.2.ms
+2.5 1 1541980172 1542066572 stddeviation.ms
+2.5 1 1541980172 1542066572 variancedist.ms
+2.5 1 1541980172 1542066572 variancedist.2.ms
--- /dev/null
+++ b/stt/mkfile
@@ -1,0 +1,16 @@
+ALL=`{ls *.t}+
+all:V: ${ALL:%.t=%.pdf}+
+%.ms:D: %.t
+ cat msglobal $prereq | pic | tbl | eqn |
+ troff -mpictures > $target
+
+%.ps:D: %.ms
+ lp -dstdout < $prereq > $target
+
+%.pdf:D: %.ps
+ ps2pdf $prereq > $target
+
+clean:
+ rm -f *.pdf *.ps *.ms
--- /dev/null
+++ b/stt/msglobal
@@ -1,0 +1,5 @@
+.FP lucidasans
+.de Bp
+.bp 0
+.po 7
+..
--- /dev/null
+++ b/stt/probacondt.t
@@ -1,0 +1,17 @@
+Soit S l'ensemble fondamental.
+Soit E un évènement arbitraire de S tel que p(E) > 0.
+La probabilité d'un évènement A se produise si E s'est produit,
+appelée probabilité conditionnelle de "A si E" s'écrit p(A|E) et s'exprime:
+
+.EQ
+P(A/E) = ?
+.EN
+.Bp
+Soit S l'ensemble fondamental.
+Soit E un évènement arbitraire de S tel que p(E) > 0.
+La probabilité d'un évènement A se produise si E s'est produit,
+appelée probabilité conditionnelle de "A si E" s'écrit p(A|E) et s'exprime:
+
+.EQ
+P(A/E) = {P(A ∩ E)} over {P(E)}+.EN
--- /dev/null
+++ b/stt/stddeviation.t
@@ -1,0 +1,7 @@
+The standard deviation of a variable X is computed as...
+.Bp
+The standard deviation of a variable X is computed as:
+
+.EQ
+s = sqrt {{sum from 0 to N ({X sub i} - {X highbar}) sup 2} over {N - 1}}+.EN
--- /dev/null
+++ b/stt/variance.2.t
@@ -1,0 +1,12 @@
+Another definition of the variance of a variable X is...
+.Bp
+Another definition of the variance of a variable X is:
+
+.EQ
+s sup 2 = {sum from 0 to N ({X sub i} - {X highbar}) sup 2} over N+.EN
+
+This is the arithmetic mean of the squared deviations from the mean.
+
+Some books choose to introduce it this way,
+and correct it by multiplying by N(N-1) in some situations.
--- /dev/null
+++ b/stt/variance.t
@@ -1,0 +1,9 @@
+The variance of a variable X is computed as...
+.Bp
+The variance of a variable X is computed as:
+
+.EQ
+s sup 2 = {sum from 0 to N ({X sub i} - {X highbar}) sup 2} over {N - 1}+.EN
+
+The substraction in the denominator is related to use of Xbar in the numerator.
--- /dev/null
+++ b/stt/variancedist.2.t
@@ -1,0 +1,9 @@
+For many types of applications,
+the interval containing most of the observations is...
+.Bp
+For many types of applications,
+the interval containing most of the observations is:
+
+.EQ
+left [ X highbar - 2s ; X highbar + 2s right ]
+.EN
--- /dev/null
+++ b/stt/variancedist.t
@@ -1,0 +1,9 @@
+For many types of applications,
+the interval containing about two thirds of the observations is...
+.Bp
+For many types of applications,
+the interval containing about two thirds of the observations is:
+
+.EQ
+left [ X highbar - s ; X highbar + s right ]
+.EN