• An explanation of what a normal distribution means, including its
shape and features.
o Explain what it means when the
normal distribution has a mean
of 80 and a standard deviation
of 14 that is above 90. Explain
how this changes when the area
is between 100 and 110.
o Explain what it means when a
score is in the 25th percentile of
a normal distribution with a
mean of 100 and a standard
deviation of 15.

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.