<image>The vision condition of elementary and middle school students is of widespread concern in society. Relevant departments in a certain city conducted a sampling survey of the vision conditions of 30,000 junior high school students. The relevant data obtained is shown in the frequency distribution histogram, as shown in the figure. The frequency ratio of the five groups from left to right is 2:4:9:7:3, with the frequency of the fifth group being 36.
(1) The number of students surveyed in this investigation is (___).
(2) The median of the data surveyed should fall within group (___).
(3) If the vision range of 4.9 to 5.1 (inclusive of 4.9 and 5.1) is considered normal, the approximate number of junior high school students in the city with normal vision is (___).