What is the different betwen parameter and estimate?

A parameter is a fixed value that characterizes a population or a model, such as the mean or standard deviation in statistics. In contrast, an estimate is a calculated approximation of a parameter based on sample data. While parameters are often unknown and represent the true characteristics of a population, estimates provide a practical way to infer those parameters using observed data. Thus, estimates can vary depending on the sample selected, whereas parameters remain constant for a given population.