Statistics always study a group of values instead of single observation studies the mass of phenomena and the conclusion on certain characteristics obtained.
For example, the study of income of one worker of a company is statistics, but the study of incomes of 50 workers of that company form statistics. In other words, the monthly income of Rs. 1,000 workers do not constitute statistics but the average income of Rs. 1000 of a group of workers of that company forms statistics.