diff --git a/reference/stats/functions/stats-dens-pmf-negative-binomial.xml b/reference/stats/functions/stats-dens-pmf-negative-binomial.xml
new file mode 100644
index 0000000000..b6a92871e8
--- /dev/null
+++ b/reference/stats/functions/stats-dens-pmf-negative-binomial.xml
@@ -0,0 +1,186 @@
+
+
+
+
+
+ stats_dens_pmf_negative_binomial
+ Probability density function of the negative binomial distribution
+
+
+
+ &reftitle.description;
+
+ floatstats_dens_pmf_negative_binomial
+ floatx
+ floatn
+ floatpi
+
+
+ Returns the probability density at x, where the
+ random variable follows the negative binomial distribution of which the number of the success
+ is n and the success rate is pi.
+
+
+
+
+ &reftitle.parameters;
+
+
+
+ x
+
+
+ The value at which the probability density is calculated
+
+
+
+
+ n
+
+
+ The number of the success of the distribution
+
+
+
+
+ pi
+
+
+ The success rate of the distribution
+
+
+
+
+
+
+
+
+ &reftitle.returnvalues;
+
+ The probability density at x or &false; for failure.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/reference/stats/functions/stats-rand-gen-noncentral-chisquare.xml b/reference/stats/functions/stats-rand-gen-noncentral-chisquare.xml
new file mode 100644
index 0000000000..68b201cfbd
--- /dev/null
+++ b/reference/stats/functions/stats-rand-gen-noncentral-chisquare.xml
@@ -0,0 +1,176 @@
+
+
+
+
+
+ stats_rand_gen_noncentral_chisquare
+ Generates a random deviate from the non-central chi-square distribution
+
+
+
+ &reftitle.description;
+
+ floatstats_rand_gen_noncentral_chisquare
+ floatdf
+ floatxnonc
+
+
+ Returns a random deviate from the non-central chi-square distribution with degrees of freedom,
+ df, and non-centrality parameter, xnonc.
+
+
+
+
+ &reftitle.parameters;
+
+
+
+ df
+
+
+ The degrees of freedom
+
+
+
+
+ xnonc
+
+
+ The non-centrality parameter
+
+
+
+
+
+
+
+
+ &reftitle.returnvalues;
+
+ A random deviate
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/reference/stats/functions/stats-stat-factorial.xml b/reference/stats/functions/stats-stat-factorial.xml
new file mode 100644
index 0000000000..7985b6721e
--- /dev/null
+++ b/reference/stats/functions/stats-stat-factorial.xml
@@ -0,0 +1,164 @@
+
+
+
+
+
+ stats_stat_factorial
+ Returns the factorial of an integer
+
+
+
+ &reftitle.description;
+
+ floatstats_stat_factorial
+ intn
+
+
+ Returns the factorial of an integer, n.
+
+
+
+
+ &reftitle.parameters;
+
+
+ n
+
+
+ An integer
+
+
+
+
+
+
+
+ &reftitle.returnvalues;
+
+ The factorial of n.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+