What is the difference between descriptive and inferential statistics?
From PsychWiki - A Collaborative Psychology Wiki
Descriptive Statistics are a group of procedures that summarize data graphically and statistically. Descriptive statistics are designed to describe a sample, and is contrasted with Inferential Statistics which is designed to draw conclusions from the sample to the larger population. - Imagine you conduct a study to determine whether males or females are happier. After collecting data on 1000 subjects you could use "Descriptive Statistics" to identify characteristics of the sample, such as the mean happiness levels, ranges of scores, standard deviation, and so forth; and you could use "Inferential Statistics" to identify if your sample of data generalizes toward the larger population of males and females beyond those in your study.