Final answer:
In regression, sb_usage represents the slope of the regression line, indicating how the dependent variable changes for every one-unit increase in the independent variable.
Step-by-step explanation:
The slope of the regression line in regression, or the amount that the dependent variable changes for each unit increase in the independent variable, is represented by the sb_usage variable. It aids in the interpretation of the variables' relationship and the evaluation of the influence of each variable on the others.
In a regression model, for instance, if test scores are the dependent variable and sb usage is the independent variable, a positive value for sb usage indicates that the test scores increase by the slope's value for each unit increase in sb usage. Comparably, for every unit rise in sb_usage, a negative result for sb_usage would indicate a decline in test_scores.