Question

A pizzeria owner wants to know which pizza topping is least liked by her customers so she can take it off the menu. She used four different methods to find this information.

Method 1: The owner asked every third customer to rate all the pizza toppings in order of preference.
Method 2: The owner gave all customers a toll-free telephone number and asked them to phone in their topping preferences.
Method 3: The owner asked the preferences of every other teenager who entered the pizzeria.
Method 4: The owner reviewed the pizzeria’s complaint cards and assessed all complaints related to pizza toppings.

Which method is most likely to give a valid generalization?

Answer 1

I suggest method 1 because it is unbiased and systematic.

The second method requires a lot on the initiatives of customers, and likely to have extreme cases only (liked very much or disliked very much).

The third is biased towards teenagers, which may not be the only category of customers who ordered pizzas.

Again, the fourth requires initiative from the customer, so biased towards customers who had something to say.

Explanation: