The correct answer is option 3, which states that nominal GDP is calculated by valuing outputs of different years at constant prices. This statement is not correct because nominal GDP is actually calculated by valuing outputs of different years at current prices.

Let`s analyze the other options to better understand them:

Option 1 states that real GDP is calculated by valuing outputs of different years at common prices. This statement is correct. Real GDP is calculated by adjusting nominal GDP for changes in price levels. This adjustment is done by using a common set of prices, usually the prices of a base year.

Option 2 states that potential GDP is the real GDP that the economy would produce if its resources were fully employed. This statement is correct. Potential GDP represents the maximum level of real GDP that an economy can sustain over the long term when all of its resources, including labor, capital, and technology, are fully utilized.

Option 4 states that real GDP per capita is the ratio of real GDP divided by population. This statement is correct. Real GDP per capita is a measure of the average economic output per person in a country. It is calculated by dividing real GDP by the total population of the country.

In summary, the correct answer is option 3, as it incorrectly states that