Question

Dr. Torres studies the relationship between soil loss in one square meter of soil and the amount of rainfall in one day. The scatter plot below shows the soil loss, in grams, and the rainfall, in millimeters, on eight different days.



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After it rains, Dr. Torres adds the same amount of soil that was lost back into the square. Based on the data and the line of best fit, about how much soil, in grams, should Dr. Torres add if it rains 23 millimeters one day and 76 millimeters the next day?


18 g


20 g


22 g


26 g

Answer 1

About 22 g.

Reason: The line of best fit is about y ≈ 0.22x (grams per mm). For 23 mm: 0.22·23 ≈ 5 g. For 76 mm: 0.22·76 ≈ 17 g. Total ≈ 5 + 17 = 22 g.