Which one of the following is the optimal way to take a sample for a study on the calorie content of sandwiches at all fast food restaurants?
randomly select a chicken sandwich and a beef burger from one of the restaurants as the sample
o create two categories, one of sandwiches and one of another menu option at all fast food restaurants, and take a random sample
from all the fast food restaurants
create two categories, one with chicken sandwiches and one with beef burgers and take a random sample from all the fast food
restaurants
categorize all the fast food restaurants into one group and take a random sample of all sandwiches