<image>In response to the call for creating an environmentally friendly model city, a high school organized 1,200 students to participate in the voluntary collection of used batteries. The following chart represents the statistics of battery collection by 50 randomly selected students.
\frac{} Based on the data in the chart, answer the following questions:
(1) The average number of used batteries collected by each of these 50 students is ______ batteries;
(2) The median number of batteries is ______, and the mode is ______;
(3) Estimate the total number of batteries collected in this event by the school to be ______ batteries;
(4) According to the information, one button battery can pollute 600 tons of water, which is equivalent to a person's lifetime drinking water. Assuming that a button battery, a AAA battery, an AA battery, and a D battery pollute water in the ratio of 1:2:3:5, how many people's lifetime drinking water can be saved by this battery collection activity?

