This document discusses key concepts in statistics including types of data, variables, and descriptive and inferential statistics. It defines statistics as the science of organizing, presenting, analyzing, and interpreting numerical data to assist in making more effective decisions. There are two main types of data - quantitative and qualitative. Variables can be discrete, continuous, nominal, ordinal, interval, or ratio. Descriptive statistics are used to summarize and present data, while inferential statistics are used to make predictions or generalizations about populations based on samples. Common descriptive and inferential statistical techniques are explained.