What is a parameter?

What is a parameter?

• A. A descriptive value of a population.
• B. A descriptive value based on a sample.
• C. A fixed value from a single observation.
• D. A measure of sampling error.

Answer: (A)

A parameter is a numerical summary that describes a characteristic of an entire population, such as the true mean μ or true proportion p. It represents the fixed value of the population, usually unknown and estimated from data. A descriptive value based on a sample is a statistic, not a parameter, because it reflects only the sampled data. A single observation is just one data point, not a summary of the whole population. A measure of sampling error concerns how far a sample-based estimate is from the population parameter, not the parameter itself.

A parameter is a numerical summary that describes a characteristic of an entire population, such as the true mean μ or true proportion p. It represents the fixed value of the population, usually unknown and estimated from data. A descriptive value based on a sample is a statistic, not a parameter, because it reflects only the sampled data. A single observation is just one data point, not a summary of the whole population. A measure of sampling error concerns how far a sample-based estimate is from the population parameter, not the parameter itself.