find the variance of all nodes in a linked list in csharp

main.cs
class Node 
{
    public int value;
    public Node next;
}

LinkedList<Node> list = new LinkedList<Node>();

double variance(LinkedList<Node> list) 
{
    double sumOfSquares = 0.0, mean = 0.0, variance;
    int count = 0;
    Node current = list.First;

    while (current != null) 
    {
        count++;
        mean += current.value;
        current = current.next;
    }

    mean /= count;
    current = list.First;

    while (current != null) 
    {
        sumOfSquares += Math.Pow(current.value - mean, 2);
        current = current.next;
    }

    variance = sumOfSquares / count;
    return variance;
}
617 chars
34 lines

main.cs
list.AddLast(new Node { value = 10 });
list.AddLast(new Node { value = 15 });
list.AddLast(new Node { value = 20 });
list.AddLast(new Node { value = 25 });
156 chars
5 lines

main.cs
double varianceResult = variance(list);
40 chars
2 lines