Two methods are used to predict how many customers will call in for help in the next four days. The first method predicts the numbers of callers to be $23,5,14,$ and $20$ for the four respective days. The second method predicts $20,13,14,$ and $20$ for the four respective days. The actual numbers of callers turn out to be $23,10,15,$ and $19.$ Which method has the smaller mean squared error $($MSE$)?$