μ (the Greek letter mu) is an example of a population parameter , specifically representing the population mean or expected value in statistics and probability theory

. It denotes the average of an entire population, as opposed to a sample statistic which would be represented by the sample mean (often denoted as xˉ\bar{x}xˉ). In summary:

• μ = population mean (population parameter)
• xˉ\bar{x}xˉ = sample mean (sample statistic)

Thus, μ is used to describe a characteristic of the whole population, such as the average height, weight, or any quantitative measure of interest