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…showed last 75 words of 623 total…fit the description can be asked to complete the survey. A stratified random sample may get round this problem. It is a quota sample where all the respondents, the people being interviewed must be chosen at random. Experiments are experimental techniques which market researchers can use. To launch a new product is often very costly. Instead, products could be tested on groups of consumers to see whether they are acceptable and likely to sell well.