Made the Go implementation a library. Test is pathetic but it's a start.

go/magic_stats/Makefile

@@ -1,10 +1,7 @@
 R_SCRIPT=C:/Users/lcthw/AppData/Local/Programs/R/R-4.6.0/bin/Rscript.exe
 
-all:
-	go build .
-
 test:
-	./magic_stats
+	go test
 
 r_test: test
 	$(R_SCRIPT) ../../cpp/tests/confirm.r

go/magic_stats/welford.go

@@ -3,9 +3,6 @@ package main
 import (
   "fmt"
   "math"
-  "math/rand/v2"
-  "os"
-  "log"
 )
 
 type Welford struct {
@@ -97,34 +94,3 @@ func (stats *Welford) TTest(second *Welford) TTest {
 
   return TTest{t_stat, dof, p_val}
 }
-
-func main() {
-  var welf Welford
-  var welf2 Welford
-  skew_factor := rand.Float64() * 10
-
-  samples_file, err := os.Create("samples.txt")
-  if err != nil { log.Fatal(err) }
-  defer samples_file.Close()
-
-  for i := 0; i < 100; i++ {
-    sample := rand.Float64() * 100
-    welf.Sample(sample)
-    welf2.Sample(sample + skew_factor)
-
-    sample_line := fmt.Sprintf("%f %f\n", sample, sample + skew_factor)
-    samples_file.Write([]byte(sample_line))
-  }
-
-  welf.Dump()
-  welf2.Dump()
-  result := welf.TTest(&welf2)
-
-  fmt.Println(
-    "----\nTTest Results:\nMean:", welf.Mean,
-    "\nVariance: ", welf.Variance(),
-    "\nStddev: ", welf.StdDev(),
-    "\nTStat: ", result.TStat,
-    "\nDOF: ", result.DOF,
-    "\nPVal: ", result.PVal);
-}

go/magic_stats/welford_test.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+  "fmt"
+  "math/rand/v2"
+  "os"
+  "log"
+  "testing"
+)
+
+func TestBasicWelford(t *testing.T) {
+  var welf Welford
+  var welf2 Welford
+  skew_factor := rand.Float64() * 10
+
+  samples_file, err := os.Create("samples.txt")
+  if err != nil { log.Fatal(err) }
+  defer samples_file.Close()
+
+  for i := 0; i < 100; i++ {
+    sample := rand.Float64() * 100
+    welf.Sample(sample)
+    welf2.Sample(sample + skew_factor)
+
+    sample_line := fmt.Sprintf("%f %f\n", sample, sample + skew_factor)
+    samples_file.Write([]byte(sample_line))
+  }
+
+  welf.Dump()
+  welf2.Dump()
+  result := welf.TTest(&welf2)
+
+  fmt.Println(
+    "----\nTTest Results:\nMean:", welf.Mean,
+    "\nVariance: ", welf.SampleVariance(),
+    "\nStddev: ", welf.StdDev(),
+    "\nTStat: ", result.TStat,
+    "\nDOF: ", result.DOF,
+    "\nPVal: ", result.PVal);
+}