/* Student's T Tester v. 0.05 Written by G. Rob Burgess 1997 Feel free to adapt for your own use. */ import java.awt.*; import java.util.*; import java.lang.*; import java.applet.*; import VisualNumerics.math.Statistics; public class Students_t05 extends Applet { public void init() { super.init(); //{{INIT_CONTROLS setLayout(null); addNotify(); resize(501,305); Compute = new java.awt.Button("Compute"); Compute.reshape(384,24,90,36); add(Compute); tScore = new java.awt.TextField(); tScore.setEditable(false); tScore.reshape(384,144,72,24); add(tScore); variB = new java.awt.TextField(); variB.setEditable(false); variB.reshape(168,252,84,24); add(variB); variA = new java.awt.TextField(); variA.setEditable(false); variA.reshape(72,252,84,24); add(variA); label7 = new java.awt.Label("Variance"); label7.reshape(0,252,72,24); add(label7); avgB = new java.awt.TextField(); avgB.setEditable(false); avgB.reshape(168,216,84,24); add(avgB); avgA = new java.awt.TextField(); avgA.setEditable(false); avgA.reshape(72,216,84,24); add(avgA); label6 = new java.awt.Label("Average"); label6.reshape(0,216,72,24); add(label6); numA = new java.awt.TextField(); numA.setEditable(false); numA.reshape(96,180,36,24); add(numA); label3 = new java.awt.Label("Data set 1"); label3.reshape(72,156,96,24); add(label3); label4 = new java.awt.Label("Data set 2"); label4.reshape(168,156,84,24); add(label4); label5 = new java.awt.Label("N"); label5.reshape(36,180,40,24); add(label5); numB = new java.awt.TextField(); numB.setEditable(false); numB.reshape(192,180,36,24); add(numB); dataB = new java.awt.TextField(); dataB.reshape(96,108,355,24); add(dataB); dataA = new java.awt.TextField(); dataA.reshape(96,72,355,24); add(dataA); label1 = new java.awt.Label("Data set 1:"); label1.reshape(0,72,84,24); add(label1); label2 = new java.awt.Label("Data set 2:"); label2.reshape(0,108,84,24); add(label2); label9 = new java.awt.Label("Student's T Tester v. 0.05 Enter data separated by commas."); label9.reshape(0,0,396,24); add(label9); label10 = new java.awt.Label("Example: 13.4,14.5,14.003,16,16.2,16"); label10.reshape(12,36,360,24); add(label10); degf = new java.awt.TextField(); degf.setEditable(false); degf.reshape(384,180,36,24); add(degf); label11 = new java.awt.Label("degrees of freedom"); label11.reshape(252,180,132,24); add(label11); label12 = new java.awt.Label("One tailed P value"); label12.reshape(252,216,132,24); add(label12); probab = new java.awt.TextField(); probab.setEditable(false); probab.reshape(384,216,72,28); add(probab); label13 = new java.awt.Label("Two tailed P value"); label13.reshape(252,252,132,24); add(label13); twoprobab = new java.awt.TextField(); twoprobab.setEditable(false); twoprobab.reshape(384,252,72,28); add(twoprobab); label8 = new java.awt.Label("T Score:"); label8.reshape(312,144,72,24); add(label8); //}} } public String getAppletInfo() { return "Student's T Tester v. 0.05. Written by G. Rob Burgess."; } public boolean action(Event event, Object arg) { // If the compute button was clicked, compute! if (event.target == Compute) { // Stuff to do when button is pressed // Read DataA // Get text from data textField String value = dataA.getText(); Stats A = new Stats(value); value = dataB.getText(); Stats B = new Stats(value); double t = (A.avg-B.avg)/(Math.sqrt(((A.n-1)*A.vari+(B.n-1)*B.vari)/(A.n+B.n-2))*Math.sqrt((1.0/A.n+1.0/B.n))); //new stuff double df = A.n + B.n - 2.0; double tt = Math.abs(t); double prob = Statistics.tCdf(tt,df); if (prob < 0.000001) { prob = 0.0; } else if (prob > 0.50) { prob = 1.0 - prob; } prob = (Math.round(prob * 10000.0)) / 10000.0; double twoprob = 2 * prob; t = (Math.round(t * 10000.0)) / 10000.0; //end new stuff Double f = new Double(A.n); numA.setText(f.toString()); f = new Double(B.n); numB.setText(f.toString()); f = new Double(A.avg); avgA.setText(f.toString()); f = new Double(B.avg); avgB.setText(f.toString()); f = new Double(A.vari); variA.setText(f.toString()); f = new Double(B.vari); variB.setText(f.toString()); f = new Double(t); tScore.setText(f.toString()); f = new Double(df); degf.setText(f.toString()); if (prob == 0.0) { probab.setText(" << 0.0001"); twoprobab.setText(" << 0.0001"); } else { f = new Double(prob); probab.setText(f.toString()); f = new Double(twoprob); twoprobab.setText(f.toString()); } } return true; } public boolean handleEvent(Event event) { return super.handleEvent(event); } //{{DECLARE_CONTROLS java.awt.Button Compute; java.awt.TextField tScore; java.awt.TextField variB; java.awt.TextField variA; java.awt.Label label7; java.awt.TextField avgB; java.awt.TextField avgA; java.awt.Label label6; java.awt.TextField numA; java.awt.Label label3; java.awt.Label label4; java.awt.Label label5; java.awt.TextField numB; java.awt.TextField dataB; java.awt.TextField dataA; java.awt.Label label1; java.awt.Label label2; java.awt.Label label9; java.awt.Label label10; java.awt.TextField degf; java.awt.Label label11; java.awt.Label label12; java.awt.TextField probab; java.awt.Label label13; java.awt.TextField twoprobab; java.awt.Label label8; //}} }