Which term best describes a numerical value that describes a population?

Which term best describes a numerical value that describes a population?

• A. Parameter
• B. Statistic
• C. Sample
• D. Sampling error

Answer: (A)

When describing a whole population with a single number, that descriptor is called a parameter. It represents a fixed property of the population, such as the population mean (mu) or the population standard deviation (sigma). In practice we rarely know these true values, so we estimate them from a sample. The numbers calculated from a sample, like the sample mean (x-bar) or sample standard deviation (s), are called statistics. They can vary from one sample to another, which is why we talk about sampling error—the difference between the population parameter and the sample statistic. So for a numerical value that describes the population, parameter is the correct term.

When describing a whole population with a single number, that descriptor is called a parameter. It represents a fixed property of the population, such as the population mean (mu) or the population standard deviation (sigma). In practice we rarely know these true values, so we estimate them from a sample. The numbers calculated from a sample, like the sample mean (x-bar) or sample standard deviation (s), are called statistics. They can vary from one sample to another, which is why we talk about sampling error—the difference between the population parameter and the sample statistic. So for a numerical value that describes the population, parameter is the correct term.