In an impoverished urban area, individual income is normally distributed with a mean of $21,000 and a standard deviation of $2,000. Use Excel to answer the following questions. What percentage of incomes fall a. below $17,000? c. between $17,000 and $25,000? d. what is an individual's income to be in the top 20%? b. above $23,000? Between what two X values (symmetrically distributed around the mean) are fifty percent. of the values? f. what is the z-score associated with an income of $12,500? g. what is the z-score associated with an income of $32,000? h. referring to f and g, which income do you consider more unusual? Explain. e.