You are surveying students to find out their opinion of the quality of food served in the school cafeteria. you decide to poll only those students who buy hot lunch at the school cafeteria on a particular day. is your sample random? explain.

Random sampling consists of population where each member has an equal probability of being chosen.

Here its given that the students who already purchase food from the cafeteria are selected for the survey. This is not random as those who are already eating from the cafeteria already likes the food. Rather the random survey would have been if you selected students from both groups- those who eat and those who do not eat. Or the survey could have been conducted for any particular food item or more than 1 day.

ok thats very interesting