1. To conduct a pre-election opinion poll on a proposed amendment to the constitution, a random sample of 10 telephone prefixes(first 3 digits of the telephone number) was selected, and all households from the phone prefixes selected were called. This sampling is defined as _____ sampling.
a)random
b)systematic
c)stratified
d)cluster
e)proportional
2)To judge a pilot of a proposed television sitcom, a random sample of 10 people from each of the three different categories was selected. Those individuals were asked to rate a pilot of a show. This sampling technique is called ___ sampling
(same choices)
3) You want to test the water supply, of a large rural area in Ontario, for water hardness levels. A map of the area was partitioned into 50 districts. Testing 3 randomly-chosen wells from each district is an example of:
(same choices)
I this that it's 1)random 2)stratified 3)clustered but I'm not sure and I need to get them right. Please help, thanks.