Question

what does a residual value of 1.3 mean when referring to the line of best fit of a data set?
a data point is 1.3 units above the line of best fit.
a data point is 1.3 units below the line of best fit.
the line of best fit has a slope of -1.3
the line of best fit has a slope of 1.3.

Explanation:

A residual is calculated as $residual = observed\ value - predicted\ value$, where the predicted value comes from the line of best fit. A positive residual means the observed data point is above the predicted value (the line of best fit). A residual of 1.3 is positive, so the data point lies 1.3 units above the line.

Answer:

A. A data point is 1.3 units above the line of best fit.