This document provides an overview of key concepts in statistics. It discusses that statistics involves collecting, organizing, analyzing and interpreting data. It also defines important statistical terms like population, sample, parameter, statistic, qualitative and quantitative data, independent and dependent variables, discrete and continuous variables, and different levels of measurement for variables. The different levels of measurement are nominal, ordinal, interval and ratio. Descriptive statistics are used to summarize and describe data, while inferential statistics allow making inferences about populations from samples.