A sample survey is a study method that involves selecting a portion of a population and asking questions to these individuals to know their opinions or insights about a particular situation. Additionally, the answers provided by the selected individuals are used to make conclusions about all the population. This method is the one used in the situation described because the store manager selects only some customers to know about the sales they prefer and would likely use this information to know the preferences of all the customers.
To answer the question, divide the fiber intake during breakfast by the total fiber intake prescribed by the doctor and multiply with 100%. With the given above,
(4 / 25) x 100% = 16%
Thus the fiber intake during breakfast constitutes 16% of the total fiber intake.