<image> In order to understand the sleep time of ninth-grade students in a school, the extracurricular activity group of this school conducted a survey on the sleep time of several ninth-grade students. After organizing the collected data, a frequency distribution histogram was drawn as shown in the figure (each rectangle in the figure includes the left endpoint but does not include the right endpoint). Please answer:

(1) The number of students surveyed is (___) people;
(2) Among the surveyed students, the number of people getting the most sleep is within the range (___), and the number of people in this range is (___) people;
(3) If there are 900 ninth-grade students in the school, and the reasonable sleep time range is 7 ≤ t < 9, then please estimate the number of ninth-grade students in this school whose sleep time is in this range (___) people