voluntary response
Very little to no confidence in results being reprenitive since the data was gatehred from a single website and was not random.
Adults in the USA
people who have used alterntive medicine and gained positive benefits
the subscribers of Comsumer Unition
People who replied
Survey
Not random since only subcribers and only people who replied, wo probably felt passionate
Adults
proportion who think drinking and driving is a seirous problem
Poeple who go to bar
every 10th person leaving bar
systematic sampleing
people who went to bar were asked about drinking and driving – clearly they will be biased since they might be drunk!!
dairy milk
proportion of milk thats not pure
farms
random milk samples
SRS
there is little bias clear in the question, but some may esist on which farms are selected to be inspected in the first place