A population parameter is a numerical value that summarizes a characteristic of an entire population. This could include measures such as the average age, total income, or proportion of a specific trait within the group. For example, if we want to know the average height of all adults in a country, that average height is a population parameter. Population parameters are often estimated using sample data, as it is usually impractical to collect information from every individual in a population. Researchers use statistical methods to infer these parameters from samples, which are smaller groups selected from the larger population, ensuring that the findings are representative of the whole group.