In a study of hospital patients, 20 hospitals were chosen at random from a list of all hospitals. Within each hospital, 10% of patients were chosen at random: (a) the sample of patients is a random...

In a study of hospital patients, 20 hospitals were chosen at random from a list of all hospitals. Within each hospital, 10% of patients were chosen at random:

(a) the sample of patients is a random sample;

(b) all hospitals had an equal chance of being chosen;

(c) all hospital patients had an equal chance of being chosen at the outset;

(d) the sample could be used to make inferences about all hospital patients at that time;

e) all possible samples of patients had an equal chance of being chosen.