Numerical expressions are convincing and, therefore, one of the most important functions of statistics is to present general statements in a precise and definite form. Statements or facts conveyed in exact quantitative terms are always more convincing than vague utterances. Statistics present facts in a precise and definite form and thus help proper comprehension of what is stated. Consider, for example, a statement sex ratio (i.e., number of females per 1000 males) is going down in India. The reader would not have a clear idea of the situation from this statement. But if we say the sex ratio has gone down from 934 in 2000 to 929 in 2010, it conveys a definite meaning. Similarly, statements like ‘there is a lot of unemployment in India’, ‘the population of India is growing at a very fast rate’, ‘the prices of various commodities are rising’, ’the number of students seeking admission to professional courses is increasing’, etc., hardly convey any worthwhile information as they do not specify the numerical dimensions involved.