function randomERProblem(form) {
var theP1 = Math.round(Math.random()*6+2);
var theP2 = Math.round(Math.random()*6+2);
var theP3 = Math.round(Math.random()*(17-theP1-theP2)+1);
var theP4 = 20 - theP1 - theP2 - theP3;
var theP1 = Math.round(theP1*5);
var theP2 = Math.round(theP2*5);
var theP3 = Math.round(theP3*5);
var theP4 = Math.round(theP4*5);
var theR1 = Math.round(Math.random()*80-30);
var theR2 = Math.round(Math.random()*80-30);
var theR3 = Math.round(Math.random()*80-30);
var theR4 = Math.round(Math.random()*80-30);
if ((theR1 < 0) && (theR2 < 0) && (theR3 < 0) && (theR4 < 0)) {
theR2 = Math.round(theR2*(-1));
theR4 = Math.round(theR4*(-1));
}
form.p1.value="" + theP1;
form.p2.value="" + theP2;
form.p3.value="" + theP3;
form.p4.value="" + theP4;
form.r1.value="" + theR1;
form.r2.value="" + theR2;
form.r3.value="" + theR3;
form.r4.value="" + theR4;
form.er.value="";
}
function findER(form) {
var theP1Str = form.p1.value;
if (!isPositiveNumber(theP1Str)) {
return false;
}
var theP2Str = form.p2.value;
if (!isPositiveNumber(theP2Str)) {
return false;
}
var theP3Str = form.p3.value;
if (!isPositiveNumber(theP3Str)) {
return false;
}
var theP4Str = form.p4.value;
if (!isPositiveNumber(theP4Str)) {
return false;
}
var theR1Str = form.r1.value;
if (!isNumber(theR1Str)) {
return false;
}
var theR2Str = form.r2.value;
if (!isNumber(theR2Str)) {
return false;
}
var theR3Str = form.r3.value;
if (!isNumber(theR3Str)) {
return false;
}
var theR4Str = form.r4.value;
if (!isNumber(theR4Str)) {
return false;
}
var theP1 = parseFloat(theP1Str);
var theP2 = parseFloat(theP2Str);
var theP3 = parseFloat(theP3Str);
var theP4 = parseFloat(theP4Str);
var theR1 = parseFloat(theR1Str);
var theR2 = parseFloat(theR2Str);
var theR3 = parseFloat(theR3Str);
var theR4 = parseFloat(theR4Str);
if ((theP1 + theP2 + theP3 + theP4) != 100) {
alert("The sum of the probabilities must equal 100\%");
return true;
}
var theER = (theP1*theR1 + theP2*theR2 + theP3*theR3 + theP4*theR4)/100;
form.er.value = "" + Math.round(theER*100)/100;
return true;
}
function helpER(form) {
var theP1Str = form.p1.value;
if (!isPositiveNumber(theP1Str)) {
return false;
}
var theP2Str = form.p2.value;
if (!isPositiveNumber(theP2Str)) {
return false;
}
var theP3Str = form.p3.value;
if (!isPositiveNumber(theP3Str)) {
return false;
}
var theP4Str = form.p4.value;
if (!isPositiveNumber(theP4Str)) {
return false;
}
var theR1Str = form.r1.value;
if (!isNumber(theR1Str)) {
return false;
}
var theR2Str = form.r2.value;
if (!isNumber(theR2Str)) {
return false;
}
var theR3Str = form.r3.value;
if (!isNumber(theR3Str)) {
return false;
}
var theR4Str = form.r4.value;
if (!isNumber(theR4Str)) {
return false;
}
var theP1 = parseFloat(theP1Str);
var theP2 = parseFloat(theP2Str);
var theP3 = parseFloat(theP3Str);
var theP4 = parseFloat(theP4Str);
var theR1 = parseFloat(theR1Str);
var theR2 = parseFloat(theR2Str);
var theR3 = parseFloat(theR3Str);
var theR4 = parseFloat(theR4Str);
if ((theP1 + theP2 + theP3 + theP4) != 100) {
alert("The sum of the probabilities must equal 100\%");
return true;
}
var theER = (theP1*theR1 + theP2*theR2 + theP3*theR3 + theP4*theR4)/100;
theER = "" + Math.round(theER*100)/100;
var theOut = "Expected Return Help";
theOut += "Expected Return Help
";
theOut += "The expected return can be calculated as follows:
";
theOut += "The probabilities are expressed in decimal form.
";
theOut += "E[R] = (" + Math.round(theP1)/100 + ")(" + Math.round(theR1*100)/100 + ") + ";
theOut += "(" + Math.round(theP2)/100 + ")(" + Math.round(theR2*100)/100 + ") + ";
theOut += "(" + Math.round(theP3)/100 + ")(" + Math.round(theR3*100)/100 + ") + ";
theOut += "(" + Math.round(theP4)/100 + ")(" + Math.round(theR4*100)/100 + ") = " + theER + "\%
";
theOut += "The Expected Return is " + theER + "\%
";
theOut += "";
theOut += "";
theOut += "";
var newWin = window.open("","","scrollbars,resizable,width=450,height=320");
if (newWin != null) {
newWin.document.write(theOut);
newWin.document.close();
newWin.focus();
}
return true;
}
function isPositiveNumber(inputStr) {
for (var i = 0; i < inputStr.length; i++) {
var oneChar = inputStr.substring(i,i+1);
if (((oneChar >= "0") && (oneChar <= "9")) || (oneChar == ".")) {
} else {
alert("Please make sure that only numbers are input.");
return false;
}
}
return true;
}
function isNumber(inputStr) {
var oneChar = inputStr.substring(0,1);
if (!((oneChar == '-') || ((oneChar >= "0") && (oneChar <= "9")) || (oneChar == "."))) {
alert("Please make sure that only numbers are input.");
return false;
}
for (var i = 1; i < inputStr.length; i++) {
oneChar = inputStr.substring(i,i+1);
if (((oneChar >= "0") && (oneChar <= "9")) || (oneChar == ".")) {
} else {
alert("Please make sure that only numbers are input.");
return false;
}
}
return true;
}