Question

Sampling bias exists when: A. the sample is representative of the population. B. the sample is not representative of the population. C. two variables are confounded. D. the effect of the independent variable can't be isolated.

Short answer

Answer: B: sampling bias exists when the sample is not representative of the population.

Step-by-step solution

Option A: Sample is representative of the population

This option suggests that the sample accurately represents the characteristics of the population, which means no sampling bias exists. So, this option is incorrect.

Option B: Sample is not representative of the population

This option correctly states that when a sample is not representative of the overall population, sampling bias exists. Therefore, this option is correct.

Option C: Two variables are confounded

Confounding variables are external factors that affect the relationship between the independent and dependent variable in a study. While confounding variables can introduce bias into a study, they are not directly related to sampling bias. So, this option is incorrect.

Option D: Effect of the independent variable can't be isolated

This option refers to a situation where the effect of the independent variable on the dependent variable cannot be separately identified. It deals with the inability to isolate the cause and effect in a study, which is not directly related to sampling bias. So, this option is incorrect. Based on the given options, the correct answer is B: sampling bias exists when the sample is not representative of the population.