The proposition that changes in the money supply have no long-run effect on real variables is known as the ________

The graph below represents the market for walnuts. Identify the values of the marginal benefit and the marginal cost at the output levels of 2,000 pounds, 4,000 pounds, and 6,000 pounds

At each of these output levels, state whether output is inefficiently high, inefficiently low, or economically efficient.

Omitted variables

A) can cause hypothesis tests to be unreliable. B) require multiple regression analyses to find. C) are usually those with t-statistics less than the critical value. D) are usually outside the confidence interval.