1) An economist wants to estimate the mean per capita income (in thousands of dollars) for a major city in Texas. He believes that the mean income is $22.2$⁢22.2, and the variance is known to be $136.89$⁢136.89. How large of a sample would be required in order to estimate the mean per capita income at the 80%80% level of confidence with an error of at most $0.51$⁢0.51? Round your answer up to the next integer.