private double getAverageByID(String id, int minimalRaters) {
int count = 0;
double total = 0.0;
for (Rater rater : myRaters) {
if (rater.hasRating(id)) {
total += rater.getRating(id);
count++;
}
}
if (count < minimalRaters) return 0.0;
return total / count;
}