Two servers in a restaurant forecast how many guests will come for dinner in the next 4 days. The server A forecasts the number of guests to be 23 for day 1, 28 for day 2, 31 for day 3, and 24 for day 4. The server B forecasts 21, 28, 31, and 26 for four respective days. The actual attendance turns out to be 26, 25, 28, and 27. Who is the better forecaster and explain why? (20 points)