To the Internal Revenue Service, the reasonableness of total itemized deductions depends on the taxpayer's adjusted gross income. Large deductions, which include charity and medical deductions, are more reasonable for taxpayers with large adjusted gross incomes. If a taxpayer claims larger than average itemized deductions for a given level of income, the chances of an IRS audit are increased. Data (in thousands of dollars) on adjusted gross income and the average or reasonable amount of itemized deductions follow.

Adjusted Gross Income Itemized Deductions ($1,000s) ($1,000s) 22 9.6 27 9.6 32 10.1 48 11.1 65 11.5 85 17.7 120 23.5(a) Develop a scatter diagram for these data with adjusted gross income as the independent variable. 30 30 30 25 25 20 20 Itemized Deductions ($1,000s) Itemized Deductions ($1,000s Itemized Deductions ($1,000s 15 15 10 10 10 . . . . 5 5 5 0 20 40 60 80 100 120 140 0 20 40 60 80 100 120 140 0 20 40 60 80 100 120 140 O Adjusted Gross Income ($1,000s) Adjusted Gross Income ($1,000s) Adjusted Gross Income ($1,000s) 30 25 20 Itemized Deductions ($1,000s) 15 10 0 20 40 60 80 100 120 140 O Adjusted Gross Income ($1,000s)