Chạy hồi quy OLS

#load package

library(readxl)
library(tidyverse)
## -- Attaching packages ----------------------------------- tidyverse 1.2.1 --
## v ggplot2 3.1.1       v purrr   0.3.2  
## v tibble  2.1.1       v dplyr   0.8.0.1
## v tidyr   0.8.3       v stringr 1.4.0  
## v readr   1.3.1       v forcats 0.4.0
## -- Conflicts -------------------------------------- tidyverse_conflicts() --
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()
library(xtable)
library(kableExtra)
## 
## Attaching package: 'kableExtra'
## The following object is masked from 'package:dplyr':
## 
##     group_rows

#Gõ lệnh hồi quy

ols <- read_excel("C:\\Users\\Windows 10\\Documents\\ols.xlsx")
reg <-lm(data=ols,DR~TobinsQ+SIZE+GRTA+NDTS+CR+ROA)
reg2 <-lm(data=ols,DR~TobinsQ^2+SIZE+GRTA+NDTS+CR+ROA)
summary(reg)
## 
## Call:
## lm(formula = DR ~ TobinsQ + SIZE + GRTA + NDTS + CR + ROA, data = ols)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.50284 -0.12170  0.01323  0.12477  0.66334 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept) -0.461783   0.139304  -3.315 0.000975 ***
## TobinsQ     -0.094295   0.012213  -7.721 5.17e-14 ***
## SIZE         0.038954   0.005054   7.707 5.71e-14 ***
## GRTA         0.029968   0.025585   1.171 0.241960    
## NDTS         0.029737   0.023481   1.266 0.205866    
## CR          -0.013899   0.001360 -10.224  < 2e-16 ***
## ROA         -0.368572   0.097118  -3.795 0.000163 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.1778 on 573 degrees of freedom
## Multiple R-squared:  0.4155, Adjusted R-squared:  0.4094 
## F-statistic: 67.89 on 6 and 573 DF,  p-value: < 2.2e-16
k1 <- xtable(reg)
kable(summary(reg)$coef, digits = 4)
Estimate Std. Error t value Pr(>|t|)
(Intercept) -0.4618 0.1393 -3.3149 0.0010
TobinsQ -0.0943 0.0122 -7.7211 0.0000
SIZE 0.0390 0.0051 7.7070 0.0000
GRTA 0.0300 0.0256 1.1713 0.2420
NDTS 0.0297 0.0235 1.2665 0.2059
CR -0.0139 0.0014 -10.2236 0.0000
ROA -0.3686 0.0971 -3.7951 0.0002
scale <-lm(data=ols,scale(DR)~0+scale(TobinsQ)+scale(SIZE)+scale(GRTA)+scale(NDTS)+scale(CR)+scale(ROA))
summary(scale)  
## 
## Call:
## lm(formula = scale(DR) ~ 0 + scale(TobinsQ) + scale(SIZE) + scale(GRTA) + 
##     scale(NDTS) + scale(CR) + scale(ROA), data = ols)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -2.17340 -0.52602  0.05717  0.53930  2.86710 
## 
## Coefficients:
##                Estimate Std. Error t value Pr(>|t|)    
## scale(TobinsQ) -0.28876    0.03737  -7.728 4.92e-14 ***
## scale(SIZE)     0.25774    0.03341   7.714 5.43e-14 ***
## scale(GRTA)     0.03936    0.03358   1.172 0.241550    
## scale(NDTS)     0.04148    0.03272   1.268 0.205471    
## scale(CR)      -0.34209    0.03343 -10.233  < 2e-16 ***
## scale(ROA)     -0.14527    0.03825  -3.798 0.000161 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.7679 on 574 degrees of freedom
## Multiple R-squared:  0.4155, Adjusted R-squared:  0.4094 
## F-statistic:    68 on 6 and 574 DF,  p-value: < 2.2e-16
h1 <- ggplot(ols,aes(x=TobinsQ, y=DR))+geom_point()
h2 <- h1+stat_smooth(method="lm",formula = y~x+I(x^2),size=.8)
h2

h3 <- ggplot(ols,aes(x=TobinsQ,y=DR,col=San))+geom_point()+stat_smooth(method="lm",formula = y~x+I(x^2),size=.8)
h3