Why can the mean, in statistics, be an estimate

Arestaurant offers delivery for their pizzas. the total cost the customer pays is the price of the pizzas, plus a delivery fee. one customer pays $23 to have 2 pizzas delivered. another customer pays $59 for 6 pizzas. how many pizzas are delivered to a customer who pays $86?

The host of a game show is holding a bag with chips to see what prizes the contestants will play for. five (5) of the chips say “new car” ten (10) of the chips say “new tv” three (3) of the chips say “trip to france” contestant named “patty” reaches into the bag. a. what is the probability of choosing a tv chip? b. what is the probability of choosing a car chip next without replacing the 1st chip? c. are these dependent or independent events?

What is the domain of the of the exponential function shown below?