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.");