Economics examines how a country’s wealth and resources are used to meet the needs of its citizens. It focuses on the production, distribution and consumption of goods and services. Two important themes are efficiency (the absence of waste in the use of resources) and equity. Economics is empirically oriented: it uses the tools of statistical and econometric analysis to test theoretical predictions against economic data. Economics is divided into two interrelated branches. Macroeconomics deals with the economy as a whole and examines the factors that determine national output and employment levels, as well as interest rates, exchange rates and the rate of inflation. Microeconomics deals with the behaviour of individual economic agents—such as consumers, firms, investors and governments—and involves the study of, among other things, how prices and quantities are determined in a given market.