10 of the 30 surveyed say 'theme park' so you would expect 1/3 of total would feel that way 1/3 * 225 =.......
Anything that selects a certain group or a smaller group would make it less accurate
so grade 7 or cafeteria would likely make it less accurate BUT it is hard to say given the info in the Q.....if the 225 students are mostly from level 7 or is all of the students are in the cafeteria, this would not be true. But the other two choices> asking more peole or more randomization would likely make it more accurate.
