diff --git a/src/main/java/info/istlab/Zemi01/Ttest.java b/src/main/java/info/istlab/Zemi01/Ttest.java
new file mode 100644
index 0000000..c0f9ee1
--- /dev/null
+++ b/src/main/java/info/istlab/Zemi01/Ttest.java
@@ -0,0 +1,208 @@
+package info.istlab.Zemi01;
+
+public class Ttest {
+    public static void main(String[] args) {
+        double[] d1 = { 321, 269, 341, 318, 297, 308, 343, 337, 329 };
+        double[] d2 = { 303, 253, 283, 333, 307, 310, 296, 265, 271 };
+        double t1, t2;
+        System.out.println(t1 = paired_t(d1, d2));
+        double p1 = tdist(t1, d1.length-1, 2);
+        System.out.println(p1);
+
+
+        System.out.println("----");
+
+        System.out.println(t2 = welch_t(d1, d2));
+        double df2 = welch_degree_of_freedom(d1, d2);
+        System.out.println("df2 = "+df2);
+        double p2 = tdist(t2,df2, 1);
+        System.out.println(p2);
+        System.out.println(studentsCdf(2, 2));
+    }
+
+    /**
+     * 合計
+     */
+    public static double sum(double[] ary) {
+        double tmp = 0;
+        for (int i = 0; i < ary.length; i++) {
+            tmp += ary[i];
+        }
+        return tmp;
+    }
+
+    /**
+     * 平均
+     */
+    public static double avg(double[] ary) {
+        double sum = sum(ary);
+        return sum / ary.length;
+    }
+
+    /**
+     * 偏差：平均値との差の2乗
+     */
+    public static double hensa(double[] ary) {
+        double avg = avg(ary);
+        double tmp = 0;
+        for (int i = 0; i < ary.length; i++) {
+            tmp += (ary[i] - avg) * (ary[i] - avg);
+        }
+        return tmp;
+    }
+
+    /**
+     * 不偏分散： 偏差を、データ数n-1 で割ったもの vars
+     */
+    public static double var(double[] ary) {
+        double hensa = hensa(ary);
+        return hensa / (ary.length - 1);
+    }
+
+    /**
+     * 標本分散： 偏差を、データ数n で割ったもの
+     */
+    public static double varp(double[] ary) {
+        double hensa = hensa(ary);
+        return hensa / (ary.length);
+    }
+
+    /**
+     * 差の配列
+     * 
+     * @param ary1
+     * @param ary2
+     * @return
+     */
+    public static double[] diffary(double[] ary1, double[] ary2) {
+        double[] ret = new double[ary1.length];
+        for (int i = 0; i < ary1.length; i++) {
+            ret[i] = ary1[i] - ary2[i];
+        }
+        return ret;
+    }
+
+    /**
+     * 対応のあるt検定の t値
+     */
+    public static double paired_t(double[] ary1, double[] ary2) {
+        // 差の平均値 / sqrt(差の不偏分散 / データ数)
+        double avg_sa = avg(diffary(ary1, ary2));
+        double var_sa = var(diffary(ary1, ary2));
+        return avg_sa / Math.sqrt(var_sa / ary1.length);
+    }
+
+    /**
+     * 対応がない(なくてもよい) t検定 Welchのt
+     */
+    public static double welch_t(double[] ary1, double[] ary2) {
+        // 不偏分散/データ数
+        double stddev1 = var(ary1) / ary1.length;
+        double stddev2 = var(ary2) / ary2.length;
+        double diff_avg = avg(ary1) - avg(ary2);
+        return diff_avg / Math.sqrt(stddev1 + stddev2);
+    }
+    public static double welch_degree_of_freedom(double[] ary1, double[] ary2){
+        // 不偏分散/データ数
+        double stddev1 = var(ary1) / ary1.length;
+        double stddev2 = var(ary2) / ary2.length;
+        double a1 = Math.pow(stddev1 + stddev2, 2);
+        double b1 = Math.pow(stddev1,2)/(ary1.length-1) + Math.pow(stddev2,2)/(ary2.length-1);
+        return a1/b1;        
+    }
+
+    /**
+     * TDIST
+     * @param x
+     * @param df
+     * @param tails
+     * @return
+     */
+    public static double tdist(double x, double deg_free, int tails){
+        return (1.0d - studentsCdf(x, deg_free)) * tails;
+    }
+    /**
+     * 
+     * http://www.java2s.com/example/java-api/java/lang/math/exp-1-32.html
+     * 
+     * 
+     * Calculates the probability from -INF to X under Student's Distribution
+     * Ported to PHP from Javascript implementation found at
+     * http://www.math.ucla.edu/~tom/distributions/tDist.html
+     * // w w w .j av a 2 s. c o m
+     * 
+     * @param x
+     * @param deg_free
+     * @return
+     */
+    public static double studentsCdf(double x, double deg_free) {
+        if (deg_free <= 0) {
+            throw new IllegalArgumentException("The degrees of freedom need to be positive.");
+        }
+
+        double A = deg_free / 2.0;
+        double S = A + 0.5;
+        double Z = deg_free / (deg_free + x * x);
+        double BT = Math.exp(logGamma(S) - logGamma(0.5) - logGamma(A) + A * Math.log(Z) + 0.5 * Math.log(1.0 - Z));
+        double betacdf;
+        if (Z < (A + 1.0) / (S + 2.0)) {
+            betacdf = BT * betinc(Z, A, 0.5);
+        } else {
+            betacdf = 1 - BT * betinc(1.0 - Z, 0.5, A);
+        }
+
+        double tcdf;
+        if (x < 0) {
+            tcdf = betacdf / 2.0;
+        } else {
+            tcdf = 1.0 - betacdf / 2.0;
+        }
+        return tcdf;
+    }
+
+    /**
+     * Log Gamma Function
+     * 
+     * @param Z
+     * @return 
+     */
+    public static double logGamma(double Z) {
+        double S = 1.0 + 76.18009173 / Z - 86.50532033 / (Z + 1.0) + 24.01409822 / (Z + 2.0)
+                - 1.231739516 / (Z + 3.0) + 0.00120858003 / (Z + 4.0) - 0.00000536382 / (Z + 5.0);
+        double LG = (Z - 0.5) * Math.log(Z + 4.5) - (Z + 4.5) + Math.log(S * 2.50662827465);
+
+        return LG;
+    }
+    /**
+     * Internal function used by StudentCdf
+     * 
+     * @param x
+     * @param A
+     * @param B
+     * @return 
+     */
+    protected static double betinc(double x, double A, double B) {
+        double A0 = 0.0;
+        double B0 = 1.0;
+        double A1 = 1.0;
+        double B1 = 1.0;
+        double M9 = 0.0;
+        double A2 = 0.0;
+        while (Math.abs((A1 - A2) / A1) > 0.00000000000000001) {
+            A2 = A1;
+            double C9 = -(A + M9) * (A + B + M9) * x / (A + 2.0 * M9) / (A + 2.0 * M9 + 1.0);
+            A0 = A1 + C9 * A0;
+            B0 = B1 + C9 * B0;
+            M9 = M9 + 1;
+            C9 = M9 * (B - M9) * x / (A + 2.0 * M9 - 1.0) / (A + 2.0 * M9);
+            A1 = A0 + C9 * A1;
+            B1 = B0 + C9 * B1;
+            A0 = A0 / B1;
+            B0 = B0 / B1;
+            A1 = A1 / B1;
+            B1 = 1.0;
+        }
+        return A1 / A;
+    }
+
+}