Which design? The following situations all require inference about a mean or means. Identify each as (1) a single sample, (2) matched pairs, or (3) two independent samples. Explain your answers.
(a) You want to estimate the average age of your store's customers.
(b) You do an SRS survey of your customers every year. One of the questions in the survey asks about customer satisfaction on a seven-point scale with the response 1 indicating "very dissatisfied" and 7 indicating "very satisfied." You want to see if the mean customer satisfaction has improved from last year.
(c) You ask an SRS of customers their opinions on each of two new floor plans for your store.