stline_forecast function
Implementation
double stline_forecast(int year, List dataset) {
// sum of y for coefA
double sum = 0;
for (int i = 0; i < dataset.length; i++) {
sum += dataset[i][1];
}
// find mid element to subtract from year in each iteration
int midElement = dataset[dataset.length ~/ 2][0];
// sum of xy for coefB
double XY = 0;
dataset.forEach((element) {
XY += (element[0] - midElement) * element[1];
});
// sum of x^2 for coefB
double XSquare = 0;
dataset.forEach((element) {
XSquare += pow(element[0] - midElement, 2);
});
double y =
coefA(sum, dataset.length) + (coefB(XY, XSquare) * (year - midElement));
return y;
}