The sample is a subset of the population. What is defined as the population in one study can serve as a sample in another. The two studies illustrated above involve finite and countable data. They illustrate that the population is determined by what you define it as in a given experiment. Parameter A number derived from knowledge of the entire population, such as the minimum of the population, or the mean of the population.
Parameters are characteristics in a population.
Statistic A number derived from observing a sample from a population of numbers. A value computed from a sample. Greek letters are usually used to represent population parameters. Motorola SCRs were tested individually. TI took a sample from the population, tested these, and then made an inference about the population.