There is often confusion between a statistic and a parameter. A statistic is a measure of some attribute of a sample from a population. Examples include mean, standard deviation, variance, quartiles, median, test statistics.
A parameter is a numerical characteristic from a population. According to Wikipedia, a parameter is sometimes taken to be unobservable, and in this case the
statistician's task is to infer what they can about the parameter based
on observations of random variables distributed according to the probability distribution in question, or, more concretely stated, based on a random sample
taken from the population of interest. In other situations, parameters
may be fixed by the nature of the sampling procedure used or the kind of
statistical procedure being carried out
Source of above paragraph is http://en.wikipedia.org/wiki/Statistical_parameter
So the easy way to distinguish between the two is S-S and P-P. Statistic and sample go together as does parameter and population.