diff --git a/ostat.go b/ostat.go
index ac1c2a0..6020fcc 100644
--- a/ostat.go
+++ b/ostat.go
@@ -7,8 +7,12 @@ import (
 
 // from http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Online_algorithm
 
+// These constants are used in initialization of the OnlineStat
 const (
+	// http://en.wikipedia.org/wiki/Statistical_population
 	Population = iota
+
+	// http://en.wikipedia.org/wiki/Sample_(statistics)
 	Sample
 )
 
@@ -37,6 +41,10 @@ func NewPopulationStat() *OnlineStat {
 	}
 }
 
+// Let's say you have already stored some values and want to start an
+// OnlineStat mid-stream; This is the function for you! Just provide it with
+// the data in the sinature, and you'll get a properly initialized OnlineStat.
+// N.b. the typ is either ostat.Population or ostat.Sample
 func MidStreamStat(n uint64, mean, stddev, min, max float64, typ uint64) *OnlineStat {
 	return &OnlineStat{
 		n:    n,
@@ -48,6 +56,7 @@ func MidStreamStat(n uint64, mean, stddev, min, max float64, typ uint64) *Online
 	}
 }
 
+// this is how you feed new values into your OnlineStat.
 func (os *OnlineStat) Push(v float64) {
 	os.n += 1
 	if v < os.Min {
@@ -62,6 +71,7 @@ func (os *OnlineStat) Push(v float64) {
 	os.m2 = os.m2 + delta*(v-os.mean)
 }
 
+// http://en.wikipedia.org/wiki/Expected_value
 func (os *OnlineStat) Mean() float64 {
 	if os.n == 0 {
 		return 0.0
@@ -69,6 +79,7 @@ func (os *OnlineStat) Mean() float64 {
 	return os.mean
 }
 
+// http://en.wikipedia.org/wiki/Variance
 func (os *OnlineStat) Variance() float64 {
 	if os.n == 0 {
 		return 0.0
@@ -76,6 +87,7 @@ func (os *OnlineStat) Variance() float64 {
 	return os.m2 / float64(os.n-os.typ)
 }
 
+// http://en.wikipedia.org/wiki/Variance
 func (os *OnlineStat) StdDev() float64 {
 	return math.Sqrt(os.Variance())
 }