Typically a statistic estimates a population parameter by applying the same, or similar, function that defines a parameter to a sample. Statistic also is the numerical value that results when the function is applied to the sample. Term Definition Descriptive Statistics Descriptive statistics are used to characterize or describe various features of the data. The average IQ of NJ college students is 125 and the average IQ of NY college students is 120. Descriptive Statistics - There are three primary categories of descriptive statistics which are discussed below.
Central tendency describes tendency of numerical data to group or cluster about a central point.
The population is then described in terms of this central point. Mean is the sum of all values divided by the total number of observations. Median is the middle value in a set of data which is sequentially ordered. Variation Variation is a measure of the dispersion or spread of the data in the population. Variance equals an average squared difference from the mean.