guard against errors being introduced into their recording of observations due to their value systems, expectations, and attitudes. This type of error is called:

i believe the answer is: returns on investments, no wages

people who belong in upper class society would most likely get there by obtaining multiple source of income, which a certain percentage of ownership for businesses. since most of them are job creator, they would most likely get their money from profit, not wages.

answer; all of the answers are correct;