  We consider the randomness of market trade as the origin of price and return
stochasticity. We look at time series of trade values and volumes as random
variables during the averaging interval {\Delta} and describe the dependences
of market-based volatilities of price and return on the volatilities and
correlations of market trade values and volumes. We describe the market-based
origin of the lower boundaries of the accuracy of macroeconomic variables and
consider, as an example, the accuracy of macroeconomic investments. We
highlight that current macroeconomic models describe relations between the 1st
order variables determined by sums of trade values or volumes. To predict
market-based volatilities of price, return, and volatilities of macroeconomic
variables, one should develop econometric methodologies, collect data, and
elaborate macroeconomic theories of the 2nd order that model the mutual
dependence of the 1st and 2nd order economic variables. The absence of
macroeconomic theories of the 2nd order means no economic basis for predictions
of market-based volatilities of price and return, as well as volatilities of
any macroeconomic variables. In turn, that limits the accuracy of forecasting
probabilities of price, return, and the accuracy of macroeconomic variables in
the best case by Gaussian distributions.
