When using the median-fit method with summary points open paren 10 comma 120 close paren , open paren 15 comma 150 close paren , and open paren 25 comma 200 close paren , what is the equation of the best-fit model?

First find the slope using the first and third summary points: (200 − 120) / (25 − 10) = 5.33. A line with this slope through (10, 120) has an intercept of 120 − 5.33(10) = 66.67. At x = 15, that line predicts about 146.67, which is 3.33 below the middle point’s y-value of 150; the median-fit method adjusts the intercept by one-third of this difference, giving 66.67 + 3.33/3 = 67.78. The model is y = 5.33x + 67.78, choice C.

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