Applied statistics is the use of statistics and statistical theory in real-life situations.
Anyone committed to empirical observation as a means of knowing the universe about us can apply statistics as a research tool. This obviously includes science but includes history and the arts as well. For example, econometrics makes heavy use of applied statistics to study the economy.
In each of these areas, we need to observe, recognize the potential for error in our observations, and plan our research to control the observational error.