Descriptive Statistics refer to various measures that are used to describe the characteristic features of the data. Such measures include measures of central tendency, measures of dispersion, etc. Graphs, tables and charts that display data are also examples of descriptive statistics. We use descriptive statistics, while computing the average marks of a sample of 10 out of 40 students from the same class without attempting any generalisation about the entire class.
Inferential Statistics on the other hand refer to statistical process of drawing valid inferences about the characteristics of population data on the basis of sample data. If the average marks of the entire class are estimated on the basis of the sample average, we would say that we are using inferential statistics.
Thus, Descriptive statistics is the field of Study concerned with Collection, Organisation, Summarisation and Analysis of Data while Inferential Statistics in addition involves drawing of inference about a set of data (Population) when only a part of data (Sample) is observed/audited.