setwd("C:/Users/Abhi/Desktop/Data Analytics/Week 4 Day 2")
salary.df <- read.csv(paste("MBA Starting Salaries Data.csv",sep=""))
head(salary.df)
##   age sex gmat_tot gmat_qpc gmat_vpc gmat_tpc s_avg f_avg quarter work_yrs
## 1  23   2      620       77       87       87   3.4  3.00       1        2
## 2  24   1      610       90       71       87   3.5  4.00       1        2
## 3  24   1      670       99       78       95   3.3  3.25       1        2
## 4  24   1      570       56       81       75   3.3  2.67       1        1
## 5  24   2      710       93       98       98   3.6  3.75       1        2
## 6  24   1      640       82       89       91   3.9  3.75       1        2
##   frstlang salary satis
## 1        1      0     7
## 2        1      0     6
## 3        1      0     6
## 4        1      0     7
## 5        1    999     5
## 6        1      0     6
summary(salary.df)
##       age             sex           gmat_tot        gmat_qpc    
##  Min.   :22.00   Min.   :1.000   Min.   :450.0   Min.   :28.00  
##  1st Qu.:25.00   1st Qu.:1.000   1st Qu.:580.0   1st Qu.:72.00  
##  Median :27.00   Median :1.000   Median :620.0   Median :83.00  
##  Mean   :27.36   Mean   :1.248   Mean   :619.5   Mean   :80.64  
##  3rd Qu.:29.00   3rd Qu.:1.000   3rd Qu.:660.0   3rd Qu.:93.00  
##  Max.   :48.00   Max.   :2.000   Max.   :790.0   Max.   :99.00  
##     gmat_vpc        gmat_tpc        s_avg           f_avg      
##  Min.   :16.00   Min.   : 0.0   Min.   :2.000   Min.   :0.000  
##  1st Qu.:71.00   1st Qu.:78.0   1st Qu.:2.708   1st Qu.:2.750  
##  Median :81.00   Median :87.0   Median :3.000   Median :3.000  
##  Mean   :78.32   Mean   :84.2   Mean   :3.025   Mean   :3.062  
##  3rd Qu.:91.00   3rd Qu.:94.0   3rd Qu.:3.300   3rd Qu.:3.250  
##  Max.   :99.00   Max.   :99.0   Max.   :4.000   Max.   :4.000  
##     quarter         work_yrs         frstlang         salary      
##  Min.   :1.000   Min.   : 0.000   Min.   :1.000   Min.   :     0  
##  1st Qu.:1.250   1st Qu.: 2.000   1st Qu.:1.000   1st Qu.:     0  
##  Median :2.000   Median : 3.000   Median :1.000   Median :   999  
##  Mean   :2.478   Mean   : 3.872   Mean   :1.117   Mean   : 39026  
##  3rd Qu.:3.000   3rd Qu.: 4.000   3rd Qu.:1.000   3rd Qu.: 97000  
##  Max.   :4.000   Max.   :22.000   Max.   :2.000   Max.   :220000  
##      satis      
##  Min.   :  1.0  
##  1st Qu.:  5.0  
##  Median :  6.0  
##  Mean   :172.2  
##  3rd Qu.:  7.0  
##  Max.   :998.0
str(salary.df)
## 'data.frame':    274 obs. of  13 variables:
##  $ age     : int  23 24 24 24 24 24 25 25 25 25 ...
##  $ sex     : int  2 1 1 1 2 1 1 2 1 1 ...
##  $ gmat_tot: int  620 610 670 570 710 640 610 650 630 680 ...
##  $ gmat_qpc: int  77 90 99 56 93 82 89 88 79 99 ...
##  $ gmat_vpc: int  87 71 78 81 98 89 74 89 91 81 ...
##  $ gmat_tpc: int  87 87 95 75 98 91 87 92 89 96 ...
##  $ s_avg   : num  3.4 3.5 3.3 3.3 3.6 3.9 3.4 3.3 3.3 3.45 ...
##  $ f_avg   : num  3 4 3.25 2.67 3.75 3.75 3.5 3.75 3.25 3.67 ...
##  $ quarter : int  1 1 1 1 1 1 1 1 1 1 ...
##  $ work_yrs: int  2 2 2 1 2 2 2 2 2 2 ...
##  $ frstlang: int  1 1 1 1 1 1 1 1 2 1 ...
##  $ salary  : int  0 0 0 0 999 0 0 0 999 998 ...
##  $ satis   : int  7 6 6 7 5 6 5 6 4 998 ...
boxplot(salary.df$age,main="Box Plot of Age of Students",col="blue",horizontal = TRUE,xlab="Age")

boxplot(salary.df$gmat_tot,main="Box Plot of GMAT Score of Students", xlab="Total GMAT score", horizontal = TRUE, col = "blue")

boxplot(salary.df$work_yrs,main="Box Plot of Total Work Experience of students", xlab="Years of work experience", horizontal = TRUE, col = "blue")

library("lattice")
attach(salary.df)
histogram( ~ salary | sex, data = salary.df, col="Red")

f1<- salary.df[ which(salary.df$satis<='7'), ]
hist(f1$satis,breaks =5,col="Yellow",xlab="Degree of Satisfaction (1=low,7=high)", main="Satisfaction of MBA students")

library(car)
scatterplot(salary ~ age,data=salary.df,
            main="Scatter plot of salary vs age",
            xlab="age",
            ylab="salary")

library(car)
scatterplot(salary ~gmat_tot,data=salary.df,
            spread=FALSE, smoother.args=list(lty=2),
            main="Scatter plot of salary vs Gmat total",
            xlab="Gmat score",
            ylab="salary")

library(corrgram)
corrgram(salary.df,lower.panel=panel.shade,
         upper.panel=panel.pie, text.panel=panel.txt,
         main="Corrgram of salary intercorrelations")

fresher <- subset(salary.df,salary!=0 & salary!=998 & salary!=999)
fresher <- xtabs(~salary+sex+age,fresher)
fresher
## , , age = 22
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 1
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  0 0
##   98000  0 0
##   99000  0 0
##   100000 0 0
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 0 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 0 0
##   115000 0 0
##   118000 0 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 23
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  1 0
##   78256  0 1
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  0 0
##   98000  1 0
##   99000  0 0
##   100000 0 1
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 1 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 0 0
##   115000 0 0
##   118000 0 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 24
## 
##         sex
## salary   1 2
##   64000  0 1
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  1 0
##   96000  1 0
##   96500  1 0
##   97000  0 0
##   98000  2 1
##   99000  0 0
##   100000 2 2
##   100400 0 0
##   101000 0 1
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 1 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 1 0
##   115000 1 0
##   118000 0 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 1 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 25
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 1
##   86000  0 1
##   88000  0 1
##   88500  0 0
##   90000  2 0
##   92000  1 1
##   93000  1 0
##   95000  3 2
##   96000  1 0
##   96500  0 0
##   97000  0 0
##   98000  0 2
##   99000  0 0
##   100000 0 1
##   100400 0 0
##   101000 0 1
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 2 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 1 0
##   110000 0 0
##   112000 0 0
##   115000 1 0
##   118000 0 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 1 0
##   220000 0 0
## 
## , , age = 26
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 1
##   85000  1 0
##   86000  0 1
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  0 0
##   96000  1 1
##   96500  0 0
##   97000  0 0
##   98000  0 1
##   99000  0 0
##   100000 0 1
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 1 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 3 0
##   106000 0 0
##   107000 1 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 0 0
##   115000 0 0
##   118000 0 0
##   120000 0 0
##   126710 1 0
##   130000 1 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 27
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 1
##   86000  0 0
##   88000  0 0
##   88500  1 0
##   90000  1 0
##   92000  1 0
##   93000  0 0
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  1 0
##   98000  1 0
##   99000  0 0
##   100000 1 0
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 1 0
##   104000 0 0
##   105000 1 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 1 0
##   108000 0 0
##   110000 0 0
##   112000 0 0
##   115000 3 0
##   118000 0 0
##   120000 1 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 28
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 1
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  1 0
##   98000  1 0
##   99000  0 1
##   100000 0 0
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 1 0
##   105000 0 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 1 0
##   110000 0 1
##   112000 0 0
##   115000 0 0
##   118000 0 0
##   120000 1 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 29
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  0 1
##   96000  0 0
##   96500  0 0
##   97000  0 0
##   98000  1 0
##   99000  0 0
##   100000 0 0
##   100400 1 0
##   101000 0 0
##   101100 1 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 0 0
##   106000 1 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 1 0
##   115000 0 0
##   118000 0 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 30
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  0 0
##   98000  0 0
##   99000  0 0
##   100000 0 0
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 1 0
##   103000 0 0
##   104000 0 0
##   105000 1 0
##   106000 1 1
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 0 0
##   115000 0 0
##   118000 0 0
##   120000 1 1
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 31
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  1 0
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  0 0
##   98000  0 0
##   99000  0 0
##   100000 1 0
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 1 0
##   105000 1 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 0 0
##   115000 0 0
##   118000 0 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 32
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  0 0
##   98000  0 0
##   99000  0 0
##   100000 0 0
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 0 0
##   106000 0 0
##   107000 0 0
##   107300 1 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 0 0
##   115000 0 0
##   118000 0 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 33
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  0 0
##   98000  0 0
##   99000  0 0
##   100000 0 0
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 0 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 0 0
##   115000 0 0
##   118000 1 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 34
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  0 0
##   98000  0 0
##   99000  0 0
##   100000 0 0
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 1 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 0 0
##   115000 0 0
##   118000 0 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 39
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  0 0
##   98000  0 0
##   99000  0 0
##   100000 0 0
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 0 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 1 0
##   115000 0 0
##   118000 0 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 0 0
##   162000 0 0
##   220000 0 0
## 
## , , age = 40
## 
##         sex
## salary   1 2
##   64000  0 0
##   77000  0 0
##   78256  0 0
##   82000  0 0
##   85000  0 0
##   86000  0 0
##   88000  0 0
##   88500  0 0
##   90000  0 0
##   92000  0 0
##   93000  0 0
##   95000  0 0
##   96000  0 0
##   96500  0 0
##   97000  0 0
##   98000  0 0
##   99000  0 0
##   100000 0 0
##   100400 0 0
##   101000 0 0
##   101100 0 0
##   101600 0 0
##   102500 0 0
##   103000 0 0
##   104000 0 0
##   105000 0 0
##   106000 0 0
##   107000 0 0
##   107300 0 0
##   107500 0 0
##   108000 0 0
##   110000 0 0
##   112000 0 0
##   115000 0 0
##   118000 0 0
##   120000 0 0
##   126710 0 0
##   130000 0 0
##   145800 0 0
##   146000 1 0
##   162000 0 0
##   220000 0 1
mytable2 <- xtabs(~salary+age,data=fresher)
mytable2
##         age
## salary   22 23 24 25 26 27 28 29 30 31 32 33 34 39 40
##   64000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   77000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   78256   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   82000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   85000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   86000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   88000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   88500   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   90000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   92000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   93000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   95000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   96000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   96500   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   97000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   98000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   99000   2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   100000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   100400  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   101000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   101100  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   101600  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   102500  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   103000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   104000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   105000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   106000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   107000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   107300  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   107500  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   108000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   110000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   112000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   115000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   118000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   120000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   126710  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   130000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   145800  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   146000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   162000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
##   220000  2  2  2  2  2  2  2  2  2  2  2  2  2  2  2
chisq.test(mytable2)
## Warning in chisq.test(mytable2): Chi-squared approximation may be incorrect
## 
##  Pearson's Chi-squared test
## 
## data:  mytable2
## X-squared = 0, df = 574, p-value = 1

Regression Analysis

ra<-lm(salary~quarter+s_avg+f_avg+age+gmat_tot+gmat_tpc+gmat_vpc+gmat_qpc,salary.df)
summary(ra)
## 
## Call:
## lm(formula = salary ~ quarter + s_avg + f_avg + age + gmat_tot + 
##     gmat_tpc + gmat_vpc + gmat_qpc, data = salary.df)
## 
## Residuals:
##    Min     1Q Median     3Q    Max 
## -64369 -38647 -28385  51442 207646 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)  
## (Intercept) 167402.3    76080.9   2.200   0.0286 *
## quarter      -5693.9     4268.8  -1.334   0.1834  
## s_avg        15122.7    13684.2   1.105   0.2701  
## f_avg        -7715.9     7059.7  -1.093   0.2754  
## age          -1216.9      863.8  -1.409   0.1601  
## gmat_tot      -331.7      221.1  -1.500   0.1347  
## gmat_tpc       453.9      439.1   1.034   0.3022  
## gmat_vpc       392.7      559.4   0.702   0.4833  
## gmat_qpc       414.4      612.4   0.677   0.4992  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 50270 on 265 degrees of freedom
## Multiple R-squared:  0.05518,    Adjusted R-squared:  0.02665 
## F-statistic: 1.934 on 8 and 265 DF,  p-value: 0.0552
ra2<-lm(salary~sex+frstlang+satis+work_yrs+quarter,salary.df)

summary(ra2)
## 
## Call:
## lm(formula = salary ~ sex + frstlang + satis + work_yrs + quarter, 
##     data = salary.df)
## 
## Residuals:
##    Min     1Q Median     3Q    Max 
## -62122 -43403  -4881  46588 195698 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 71445.525  15586.033   4.584 7.00e-06 ***
## sex          3398.218   6728.843   0.505  0.61396    
## frstlang    -7186.851   9025.303  -0.796  0.42656    
## satis         -45.884      7.834  -5.857 1.37e-08 ***
## work_yrs     -665.349    900.024  -0.739  0.46040    
## quarter     -7327.600   2641.650  -2.774  0.00593 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 47580 on 268 degrees of freedom
## Multiple R-squared:  0.144,  Adjusted R-squared:  0.128 
## F-statistic: 9.014 on 5 and 268 DF,  p-value: 6.211e-08

Unplaced students.

unplaced <- subset(salary.df,salary==0)
summary(unplaced)
##       age             sex           gmat_tot        gmat_qpc    
##  Min.   :22.00   Min.   :1.000   Min.   :450.0   Min.   :28.00  
##  1st Qu.:25.00   1st Qu.:1.000   1st Qu.:570.0   1st Qu.:68.25  
##  Median :27.00   Median :1.000   Median :610.0   Median :82.00  
##  Mean   :28.51   Mean   :1.256   Mean   :614.3   Mean   :78.91  
##  3rd Qu.:29.75   3rd Qu.:1.750   3rd Qu.:650.0   3rd Qu.:93.00  
##  Max.   :48.00   Max.   :2.000   Max.   :760.0   Max.   :99.00  
##     gmat_vpc        gmat_tpc         s_avg           f_avg      
##  Min.   :22.00   Min.   : 0.00   Min.   :2.000   Min.   :0.000  
##  1st Qu.:70.25   1st Qu.:73.50   1st Qu.:2.800   1st Qu.:2.750  
##  Median :81.00   Median :86.00   Median :3.000   Median :3.000  
##  Mean   :77.63   Mean   :82.29   Mean   :3.031   Mean   :3.062  
##  3rd Qu.:89.00   3rd Qu.:93.00   3rd Qu.:3.300   3rd Qu.:3.250  
##  Max.   :99.00   Max.   :99.00   Max.   :3.900   Max.   :4.000  
##     quarter         work_yrs         frstlang         salary 
##  Min.   :1.000   Min.   : 0.000   Min.   :1.000   Min.   :0  
##  1st Qu.:2.000   1st Qu.: 2.000   1st Qu.:1.000   1st Qu.:0  
##  Median :2.500   Median : 3.000   Median :1.000   Median :0  
##  Mean   :2.544   Mean   : 4.589   Mean   :1.089   Mean   :0  
##  3rd Qu.:3.000   3rd Qu.: 5.000   3rd Qu.:1.000   3rd Qu.:0  
##  Max.   :4.000   Max.   :22.000   Max.   :2.000   Max.   :0  
##      satis      
##  Min.   :4.000  
##  1st Qu.:5.000  
##  Median :6.000  
##  Mean   :5.622  
##  3rd Qu.:6.000  
##  Max.   :7.000
attach(unplaced)
## The following objects are masked from salary.df:
## 
##     age, f_avg, frstlang, gmat_qpc, gmat_tot, gmat_tpc, gmat_vpc,
##     quarter, s_avg, salary, satis, sex, work_yrs
chisq.test(work_yrs,satis)
## Warning in chisq.test(work_yrs, satis): Chi-squared approximation may be
## incorrect
## 
##  Pearson's Chi-squared test
## 
## data:  work_yrs and satis
## X-squared = 44.974, df = 48, p-value = 0.5976