Mixing
lm function flipping order of interaction terms
Suppose I run the following regression:
lm(mpg ~ wt+gear+cyl+cyl:wt+cyl:gear, data=mtcars)
Coefficients:
(Intercept) wt gear cyl wt:cyl gear:cyl
46.2774 -7.9976 1.6356 -2.2755 0.6852 -0.3135
As seen, the lm function automatically inverts the interaction terms in the output when the second interacted variable is included before: it names the regressors as "wt:cyl" and "gear:cyl", not as "cyl:wt" and "cyl:gear", as I inputed in the regression formula.
This is annoying to me because I later refer to the variable names to export the results. Is there a way to make the lm function keep the interaction terms in the order that you write the equation?
r lm
asked Nov 19 '18 at 17:48
Gabriel Oliva C. Cunha
61
add a comment |
Suppose I run the following regression:
lm(mpg ~ wt+gear+cyl+cyl:wt+cyl:gear, data=mtcars)
Coefficients:
(Intercept) wt gear cyl wt:cyl gear:cyl
46.2774 -7.9976 1.6356 -2.2755 0.6852 -0.3135
As seen, the lm function automatically inverts the interaction terms in the output when the second interacted variable is included before: it names the regressors as "wt:cyl" and "gear:cyl", not as "cyl:wt" and "cyl:gear", as I inputed in the regression formula.
This is annoying to me because I later refer to the variable names to export the results. Is there a way to make the lm function keep the interaction terms in the order that you write the equation?
r lm
asked Nov 19 '18 at 17:48
Gabriel Oliva C. Cunha
61
Why not write the interaction terms first?lm(mpg ~ cyl:wt+cyl:gear + wt + cyl + gear, data=mtcars)
– thc
Nov 19 '18 at 17:52
Your formula is equivalent tolm(mpg ~ cyl*wt + cyl*gear, mtcars). And nowcylalways comes first.
– Rui Barradas
Nov 19 '18 at 17:54
add a comment |
Suppose I run the following regression:
lm(mpg ~ wt+gear+cyl+cyl:wt+cyl:gear, data=mtcars)
Coefficients:
(Intercept) wt gear cyl wt:cyl gear:cyl
46.2774 -7.9976 1.6356 -2.2755 0.6852 -0.3135
As seen, the lm function automatically inverts the interaction terms in the output when the second interacted variable is included before: it names the regressors as "wt:cyl" and "gear:cyl", not as "cyl:wt" and "cyl:gear", as I inputed in the regression formula.
This is annoying to me because I later refer to the variable names to export the results. Is there a way to make the lm function keep the interaction terms in the order that you write the equation?
r lm
asked Nov 19 '18 at 17:48
Gabriel Oliva C. Cunha
61
Suppose I run the following regression:
lm(mpg ~ wt+gear+cyl+cyl:wt+cyl:gear, data=mtcars)
Coefficients:
(Intercept) wt gear cyl wt:cyl gear:cyl
46.2774 -7.9976 1.6356 -2.2755 0.6852 -0.3135
As seen, the lm function automatically inverts the interaction terms in the output when the second interacted variable is included before: it names the regressors as "wt:cyl" and "gear:cyl", not as "cyl:wt" and "cyl:gear", as I inputed in the regression formula.
This is annoying to me because I later refer to the variable names to export the results. Is there a way to make the lm function keep the interaction terms in the order that you write the equation?
r lm
r lm
asked Nov 19 '18 at 17:48
Gabriel Oliva C. Cunha
61
asked Nov 19 '18 at 17:48
Gabriel Oliva C. Cunha
61
asked Nov 19 '18 at 17:48
Gabriel Oliva C. Cunha
61
asked Nov 19 '18 at 17:48
Gabriel Oliva C. Cunha
61
asked Nov 19 '18 at 17:48
Gabriel Oliva C. Cunha
61
61
Why not write the interaction terms first?lm(mpg ~ cyl:wt+cyl:gear + wt + cyl + gear, data=mtcars)
– thc
Nov 19 '18 at 17:52
Your formula is equivalent tolm(mpg ~ cyl*wt + cyl*gear, mtcars). And nowcylalways comes first.
– Rui Barradas
Nov 19 '18 at 17:54
add a comment |
Why not write the interaction terms first?lm(mpg ~ cyl:wt+cyl:gear + wt + cyl + gear, data=mtcars)
– thc
Nov 19 '18 at 17:52
Your formula is equivalent tolm(mpg ~ cyl*wt + cyl*gear, mtcars). And nowcylalways comes first.
– Rui Barradas
Nov 19 '18 at 17:54
Why not write the interaction terms first?
lm(mpg ~ cyl:wt+cyl:gear + wt + cyl + gear, data=mtcars)– thc
Nov 19 '18 at 17:52
Why not write the interaction terms first?
lm(mpg ~ cyl:wt+cyl:gear + wt + cyl + gear, data=mtcars)– thc
Nov 19 '18 at 17:52
Your formula is equivalent to
lm(mpg ~ cyl*wt + cyl*gear, mtcars). And now cyl always comes first.– Rui Barradas
Nov 19 '18 at 17:54
Your formula is equivalent to
lm(mpg ~ cyl*wt + cyl*gear, mtcars). And now cyl always comes first.– Rui Barradas
Nov 19 '18 at 17:54
add a comment |
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Why not write the interaction terms first?
lm(mpg ~ cyl:wt+cyl:gear + wt + cyl + gear, data=mtcars)– thc
Nov 19 '18 at 17:52
Your formula is equivalent to
lm(mpg ~ cyl*wt + cyl*gear, mtcars). And nowcylalways comes first.– Rui Barradas
Nov 19 '18 at 17:54