Which most accurately characterizes the method used to calculate inflation? researchers observe the interest rate at two points in time and infer the rate of inflation from the difference. analysts measure the cost of a bundle of goods representative of overall spending at two points in time and compare the difference in cost. economists measure change in the prices of three goods (gasoline, gold, and wheat) thought to be important determinants of the health of the economy. government workers poll households to find out how much change there is in the prices that they are paying. bureaucrats evaluate changes in the price of a nation's currency in terms of other prominent world currencies.

The business cycle is the periodic but irregular up-and-down movement in economic activity, measured by fluctuations in real gross domestic product (gdp) and other macroeconomic variables. a business cycle is typically characterized by four phases—recession, recovery, growth, and decline—that repeat themselves over time. economists note, however, that complete business cycles vary in length. the duration of business cycles can be anywhere from about two to twelve years, with most cycles averaging six years in length. some business analysts use the business cycle model and terminology to study and explain fluctuations in business inventory and other individual elements of corporate operations. but the term "business cycle" is still primarily associated with larger (industry-wide, regional, national, or even international) business trends.

Gamma-rays can kill living cells, a fact which medicine uses to its advantage, using gamma-rays to kill cancerous cells.