Statistic Vs Parameter

Population: When we collect all the items of a particular type, it is considered as a population.

Parameter: It is the metric which we get after summarizing population

E.g. Average age of all the people on earth. This average value is considered as Parameter

Sample: A sample is a part/subset of a population.

Statistic: It is the metric which we get after summarizing a sample

E.g. Average age of any 100 people on earth. This average value is considered as Statistic