A fitness center is interested in the mean amount of time a client exercises in the center each week, so they send out a survey to 100 randomly selected clients. a. the mean amount of time for all clients b. the number of hours per week a client exercises c. all fitness center clients d. the 100 clients surveyed e. the mean amount of time for the 100 clients surveyed f. a specific number of hours reported by a single client, sych as 2, 3, 4.5, etc