// PSP Dashboard - Data Automation Tool for PSP-like processes
// Copyright (C) 1999 United States Air Force
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
// The author(s) may be contacted at:
// OO-ALC/TISHD
// Attn: PSP Dashboard Group
// 6137 Wardleigh Road
// Hill AFB, UT 84056-5843
//
// E-Mail POC: ken.raisor@hill.af.mil
import pspdash.data.Correlation;
import pspdash.data.LinearRegression;
import java.io.PrintWriter;
import java.util.Vector;
class RegressionMethod extends Method {
LinearRegression l;
Correlation c;
public RegressionMethod(HistData data, double estObjLOC,
int xCol, int yCol,
String letter, String purpose) {
super(data, estObjLOC, letter, purpose);
Vector dataPoints = data.getXYDataPoints(xCol, yCol);
l = new LinearRegression(dataPoints);
c = new Correlation(dataPoints);
if (dataPoints.size() < 3 ||
badDouble(l.beta0) || badDouble(l.beta1) ||
badDouble(c.r) || badDouble(c.p)) {
errorMessages.add("You do not have enough historical data.");
rating = CANNOT_CALCULATE;
return;
}
l.project(estObjLOC, 0.70); // 70 percent prediction interval
rateBetas(true, l.beta0, l.projection, l.beta1,
getExpectedBeta1(), getExpectedBeta1Text());
if (rating > 0) {
observations.add("Your regression parameters are within bounds ("+
BETA0 + " = " + formatNumber(l.beta0) + ", " +
BETA1 + " = " + formatBeta1(l.beta1) + ").");
rateCorrelation();
}
}
public void rateCorrelation() {
double rSquared = c.r * c.r;
String statement = "(" + RSQ + " = " + formatNumber(rSquared) + ").";
if (rSquared > 0.9) {
observations.add
("In addition, the historical data points have an excellent "+
"correlation "+ statement);
rating += 2;
} else if (rSquared > 0.7) {
observations.add
("In addition, the historical data points have a strong "+
"correlation "+ statement);
rating += 1;
} else if (rSquared > 0.5) {
observations.add
("The historical data points have an adequate correlation "+
statement);
} else {
rating = SERIOUS_PROBLEM;
errorMessages.add
("The correlation between your historical data points is not "+
"reliable for planning purposes "+ statement);
return;
}
statement = "(" + PROB + " = " + formatNumber(c.p*100) + "%)";
if (c.p <= 0.05) {
observations.add
("This correlation appears to be significant " + statement);
rating += 0.5;
} else if (c.p <= 0.20) {
observations.add
("This correlation is probably significant " + statement);
rating += 0.2;
} else if (c.p <= 0.20) {
observations.add
("This correlation is likely to be significant " + statement);
} else {
observations.add
("However, this correlation may not be significant " +
statement);
rating -= 0.5;
}
}
public static final String RSQ =
"<a href='params.htm' "+probe.LINK_ATTRS+">r<sup>2</sup></a>";
public static final String PROB =
"<a href='params.htm' "+probe.LINK_ATTRS+">p</a>";
void printOption(PrintWriter out, boolean isSelected) {
printOption(out, l.projection, isSelected, l.beta0, l.beta1, l.range,
0.70, (c.r * c.r));
}
void printTableRow(PrintWriter out, boolean isSelected) {
printTableRow(out, l.projection, isSelected, l.beta0, l.beta1,
l.range, (c.r * c.r), l.stddev);
}
}