Java Utililty Methods Collection Mean

int count = 0;
double total = 0.0;
final Iterator<? extends Number> iterator = values.iterator();
while (iterator.hasNext()) {
    final double value = iterator.next().doubleValue();
    if (!Double.isNaN(value) && !Double.isInfinite(value)) {
        total += value;
        count++;
...

if (values.isEmpty()) {
    throw new IllegalArgumentException("can't calculate a mean for an empty collection");
} else {
    double sum = 0.0;
    for (Number currValue : values) {
        sum += currValue.doubleValue();
    return sum / values.size();
...

if (values == null || values.isEmpty()) {
    throw new IllegalArgumentException("Can not calculate mean of null or empty collection!");
return (calcSum(values) / values.size());

double sum = 0.0;
for (double d : data) {
    sum += d;
return sum / data.size();

int l = cluster.iterator().next().length;
double[] r = new double[l];
for (double[] d : cluster)
    for (int i = 0; i < l; i++)
        r[i] += d[i];
for (int i = 0; i < l; i++)
    r[i] /= cluster.size();
return r;
...

final int size = collection.size();
final List<T> sorted = new ArrayList<T>(collection);
Collections.sort(sorted, new Comparator<T>() {
    @Override
    public int compare(final T n1, final T n2) {
        return (int) Math.signum(n2.doubleValue() - n1.doubleValue());
});
...

double result = Double.NaN;
if (data != null && data.size() > 0 && mean != null) {
    double sum = 0.0;
    for (final Number n : data) {
        final double diff = n.doubleValue() - mean.doubleValue();
        sum = sum + (diff * diff);
    result = sum / (data.size());
...

if (coll == null || coll.size() < 1)
    throw new IllegalArgumentException();
double res = 0;
for (Number n : coll) {
    res += n.doubleValue();
return res / coll.size();

if (nums == null || nums.isEmpty()) {
    return Double.NaN;
double sum = 0.0;
for (Number n : nums) {
    sum += n.doubleValue();
return sum / nums.size();
...

return (sum(data) / (double) data.size());