corrected some pages

Several small corrections were done to several proofs and definitions.

Author: JoramSoch

P/mult-test.md

@@ -73,13 +73,13 @@ $$
 such that the probability of observing the counts $y$, given $H_0$, is
 
 $$ \label{eq:Pr0-y}
-\mathrm{Pr}(y \vert H_0) = n! \prod_{j=1}^k \frac{{p_{0i}}^{y_j}}{y_j!} \; .
+\mathrm{Pr}(y \vert H_0) = n! \prod_{j=1}^k \frac{ {p_{0i}}^{y_j} }{y_j!} \; .
 $$
 
 The probability of observing any other set of counts $x$, given $H_0$, is
 
 $$ \label{eq:Pr0-x}
-\mathrm{Pr}(x \vert H_0) = n! \prod_{j=1}^k \frac{{p_{0i}}^{x_j}}{x_j!} \; .
+\mathrm{Pr}(x \vert H_0) = n! \prod_{j=1}^k \frac{ {p_{0i}}^{x_j} }{x_j!} \; .
 $$
 
 The [p-value](/D/pval) is the probability of observing a value of the [test statistic](/D/tstat) that is as extreme or more extreme then the actually observed test statistic. Any set of counts $x$ might be considered as extreme or more extreme than the actually observed counts $y$, if the former is equally probable or less probably than the latter: