Question

a random sample of people is chosen to participate in a survey. for the survey results to be considered valid, which must be true of the random sample?
the sample must represent the target population.
the sample must be a group separate from the population.
the sample must be biased.
the sample must be the same size as the population.

Explanation:

Step1: Understand the concept of a valid random sample

A random sample is valid when it accurately represents the characteristics of the population it is drawn from.

Step2: Analyze each option

• Option 1: "The sample must represent the target population" - This is a key requirement for a valid sample. If the sample doesn't represent the target population, the survey results won't be meaningful for that population.
• Option 2: "The sample must be a group separate from the population" - A sample is part of the population, not separate. So this is incorrect.
• Option 3: "The sample must be biased" - A biased sample leads to inaccurate results and is not valid. So this is incorrect.
• Option 4: "The sample must be the same size as the population" - A sample is a subset of the population. It can't be the same size (except in trivial cases where the population is size 1). So this is incorrect.

Answer:

The sample must represent the target population.