Untitled

My models:

summary(m1)

## 
## Call:
## lm(formula = len ~ dose, data = ToothGrowth)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -8.4496 -2.7406 -0.7452  2.8344 10.1139 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)   7.4225     1.2601    5.89 2.06e-07 ***
## dose          9.7636     0.9525   10.25 1.23e-14 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 4.601 on 58 degrees of freedom
## Multiple R-squared:  0.6443, Adjusted R-squared:  0.6382 
## F-statistic: 105.1 on 1 and 58 DF,  p-value: 1.233e-14

summary(m2)

## 
## Call:
## lm(formula = len ~ supp + dose, data = ToothGrowth)
## 
## Residuals:
##    Min     1Q Median     3Q    Max 
## -6.600 -3.700  0.373  2.116  8.800 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)   9.2725     1.2824   7.231 1.31e-09 ***
## suppVC       -3.7000     1.0936  -3.383   0.0013 ** 
## dose          9.7636     0.8768  11.135 6.31e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 4.236 on 57 degrees of freedom
## Multiple R-squared:  0.7038, Adjusted R-squared:  0.6934 
## F-statistic: 67.72 on 2 and 57 DF,  p-value: 8.716e-16

Explanation

library(stargazer)

stargazer(m1, m2, type = "html")

	Dependent variable:
	len
	(1)	(2)
suppVC		-3.700***
		(1.094)
dose	9.764***	9.764***
	(0.953)	(0.877)
Constant	7.423***	9.272***
	(1.260)	(1.282)
Observations	60	60
R2	0.644	0.704
Adjusted R2	0.638	0.693
Residual Std. Error	4.601 (df = 58)	4.236 (df = 57)
F Statistic	105.065*** (df = 1; 58)	67.718*** (df = 2; 57)
Note:	p<0.1; p<0.05; p<0.01