One of:
        "earth" (default) Residuals from the lm fit on bx.
        "response"
            Residuals as above, but for earth-glm models
            return the glm response residuals.
        "standardize" Residuals divided by se * sqrt(1 - h_ii).
See the standardize argument of plot.earth.
        "delever" Residuals divided by sqrt(1 - h_ii).
See the delever argument of plot.earth.
The following options are for earth-glm models.
They return the GLM residuals (from the glm fit on bx).
See residuals.glm for details:
        "deviance"
        "pearson"
        "working"
        "partial"
The following options for earth-glm models are redundant.
They are provided for compatibility with older versions of earth or other functions:
        "glm.response" same as "response"
        "glm.deviance" same as "deviance"
        "glm.pearson" same as "pearson"
        "glm.working" same as "working"
        "glm.partial" same as "partial"