void page4() {
  String t = "Step 4 - The Test Statistics";
  textFont(myboldfont, 18);
  text(t, 30, 194);

  if (aStudy.known == 1) {
    image(test1, 260, 227);

    t = "Plugging in Y bar as " + nf(aStudy.mean, 1, 2) + ", mu zero as " + nf(aStudy.muo, 1, 2) + ", sigma as " 
      + nf(aStudy.sd, 1, 2) + ", and n as " + aStudy.samplesize + " gives a z* value of " + nf(testvalue, 1, 4)+".";
    drawStrings(t, 80, 320, 25);
  } 
  else if (aStudy.samplesize > 30) {
    image(test2, 260, 227);

    t = "Plugging in Y bar as " + nf(aStudy.mean, 1, 2) + ", mu zero as " + nf(aStudy.muo, 1, 2) + ", S as " 
      + nf(aStudy.sd, 1, 2) + ", and n as " + aStudy.samplesize + " gives a z* value of " + nf(testvalue, 1, 4) +".";

    drawStrings(t, 80, 320, 25);
  } 
  else {   
    image(test3, 260, 227);

    t = "Plugging in Y bar as " + nf(aStudy.mean, 1, 2) + ", mu zero as " + nf(aStudy.muo, 1, 2) + ", S as " 
      + nf(aStudy.sd, 1, 2) + ", and n as " + aStudy.samplesize + " gives a t* value of " + nf(testvalue, 1, 4)+".";

    drawStrings(t, 80, 320, 25);
  }
}