Joe sold gold coins for $1000 that he bought a year ago for $1000. He says, "At least I didn't lose any money on my financial investment." His economist friend points out that in effect he did lose money, because he could have received a 3 percent return on the $1000 if he had bought a bank certificate of deposit instead of the coins. The economist's analysis in this case incorporates the idea of what?
opportunity costs T/F

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.