Reading dataset into R

    airline.df <- read.csv(paste("SixAirlinesDataV2.csv",sep = ""))
    View(airline.df)

Summary Statistics using describe command

    library(psych)
    describe(airline.df)
##                     vars   n    mean      sd  median trimmed     mad   min
## Airline*               1 458    3.01    1.65    2.00    2.89    1.48  1.00
## Aircraft*              2 458    1.67    0.47    2.00    1.71    0.00  1.00
## FlightDuration         3 458    7.58    3.54    7.79    7.57    4.81  1.25
## TravelMonth*           4 458    2.56    1.17    3.00    2.58    1.48  1.00
## IsInternational*       5 458    1.91    0.28    2.00    2.00    0.00  1.00
## SeatsEconomy           6 458  202.31   76.37  185.00  194.64   85.99 78.00
## SeatsPremium           7 458   33.65   13.26   36.00   33.35   11.86  8.00
## PitchEconomy           8 458   31.22    0.66   31.00   31.26    0.00 30.00
## PitchPremium           9 458   37.91    1.31   38.00   38.05    0.00 34.00
## WidthEconomy          10 458   17.84    0.56   18.00   17.81    0.00 17.00
## WidthPremium          11 458   19.47    1.10   19.00   19.53    0.00 17.00
## PriceEconomy          12 458 1327.08  988.27 1242.00 1244.40 1159.39 65.00
## PricePremium          13 458 1845.26 1288.14 1737.00 1799.05 1845.84 86.00
## PriceRelative         14 458    0.49    0.45    0.36    0.42    0.41  0.02
## SeatsTotal            15 458  235.96   85.29  227.00  228.73   90.44 98.00
## PitchDifference       16 458    6.69    1.76    7.00    6.76    0.00  2.00
## WidthDifference       17 458    1.63    1.19    1.00    1.53    0.00  0.00
## PercentPremiumSeats   18 458   14.65    4.84   13.21   14.31    2.68  4.71
##                         max   range  skew kurtosis    se
## Airline*               6.00    5.00  0.61    -0.95  0.08
## Aircraft*              2.00    1.00 -0.72    -1.48  0.02
## FlightDuration        14.66   13.41 -0.07    -1.12  0.17
## TravelMonth*           4.00    3.00 -0.14    -1.46  0.05
## IsInternational*       2.00    1.00 -2.91     6.50  0.01
## SeatsEconomy         389.00  311.00  0.72    -0.36  3.57
## SeatsPremium          66.00   58.00  0.23    -0.46  0.62
## PitchEconomy          33.00    3.00 -0.03    -0.35  0.03
## PitchPremium          40.00    6.00 -1.51     3.52  0.06
## WidthEconomy          19.00    2.00 -0.04    -0.08  0.03
## WidthPremium          21.00    4.00 -0.08    -0.31  0.05
## PriceEconomy        3593.00 3528.00  0.51    -0.88 46.18
## PricePremium        7414.00 7328.00  0.50     0.43 60.19
## PriceRelative          1.89    1.87  1.17     0.72  0.02
## SeatsTotal           441.00  343.00  0.70    -0.53  3.99
## PitchDifference       10.00    8.00 -0.54     1.78  0.08
## WidthDifference        4.00    4.00  0.84    -0.53  0.06
## PercentPremiumSeats   24.69   19.98  0.71     0.28  0.23

Summary Statistics using summary command

    summary(airline.df)
##       Airline      Aircraft   FlightDuration   TravelMonth
##  AirFrance: 74   AirBus:151   Min.   : 1.250   Aug:127    
##  British  :175   Boeing:307   1st Qu.: 4.260   Jul: 75    
##  Delta    : 46                Median : 7.790   Oct:127    
##  Jet      : 61                Mean   : 7.578   Sep:129    
##  Singapore: 40                3rd Qu.:10.620              
##  Virgin   : 62                Max.   :14.660              
##       IsInternational  SeatsEconomy    SeatsPremium    PitchEconomy  
##  Domestic     : 40    Min.   : 78.0   Min.   : 8.00   Min.   :30.00  
##  International:418    1st Qu.:133.0   1st Qu.:21.00   1st Qu.:31.00  
##                       Median :185.0   Median :36.00   Median :31.00  
##                       Mean   :202.3   Mean   :33.65   Mean   :31.22  
##                       3rd Qu.:243.0   3rd Qu.:40.00   3rd Qu.:32.00  
##                       Max.   :389.0   Max.   :66.00   Max.   :33.00  
##   PitchPremium    WidthEconomy    WidthPremium    PriceEconomy 
##  Min.   :34.00   Min.   :17.00   Min.   :17.00   Min.   :  65  
##  1st Qu.:38.00   1st Qu.:18.00   1st Qu.:19.00   1st Qu.: 413  
##  Median :38.00   Median :18.00   Median :19.00   Median :1242  
##  Mean   :37.91   Mean   :17.84   Mean   :19.47   Mean   :1327  
##  3rd Qu.:38.00   3rd Qu.:18.00   3rd Qu.:21.00   3rd Qu.:1909  
##  Max.   :40.00   Max.   :19.00   Max.   :21.00   Max.   :3593  
##   PricePremium    PriceRelative      SeatsTotal  PitchDifference 
##  Min.   :  86.0   Min.   :0.0200   Min.   : 98   Min.   : 2.000  
##  1st Qu.: 528.8   1st Qu.:0.1000   1st Qu.:166   1st Qu.: 6.000  
##  Median :1737.0   Median :0.3650   Median :227   Median : 7.000  
##  Mean   :1845.3   Mean   :0.4872   Mean   :236   Mean   : 6.688  
##  3rd Qu.:2989.0   3rd Qu.:0.7400   3rd Qu.:279   3rd Qu.: 7.000  
##  Max.   :7414.0   Max.   :1.8900   Max.   :441   Max.   :10.000  
##  WidthDifference PercentPremiumSeats
##  Min.   :0.000   Min.   : 4.71      
##  1st Qu.:1.000   1st Qu.:12.28      
##  Median :1.000   Median :13.21      
##  Mean   :1.633   Mean   :14.65      
##  3rd Qu.:3.000   3rd Qu.:15.36      
##  Max.   :4.000   Max.   :24.69

Plot of Premium Economy vs Economy seat price

    plot(~PriceEconomy + PricePremium, data=airline.df, main="Premium Economy Price vs. Economy Price")
    abline(0,1)

Economy Pricing

    hist(airline.df$PriceEconomy, xlab="Economy Seat prices",col="lightblue", main="Economoy seat pricing")

    boxplot(airline.df$PriceEconomy,col="blue")

Premium Economy Pricing

    hist(airline.df$PricePremium, xlab="Economy Seat prices",col="lightblue", main="Economoy seat pricing")

boxplot(airline.df$PricePremium,col="blue")

Economy seats

    hist(airline.df$SeatsEconomy, xlab="Seats Economy",col = "lightblue",main = "Economy class")

    boxplot(airline.df$SeatsEconomy,col="blue")

Premium Economy Seats

    hist(airline.df$SeatsPremium, xlab="Seats Economy",col = "lightblue",main = "Economy class")

    boxplot(airline.df$SeatsPremium,col="blue")

Boxplot to show the variations in economy seats between different aircrafts

boxplot(airline.df$SeatsEconomy ~ airline.df$Aircraft, horizontal=TRUE, yaxt="n", ylab="Aircraft", xlab="SeatsEconomy", main="Aircraft Vs. SeatsEconomy", col=c("blue", "green"))
axis(side=2, at=c(1,2), labels = c("Boeing", "Airbus"))

Scatterplot Matrix for PriceEconomy and PricePremium

   library(car)
    scatterplotMatrix(formula = ~ PriceEconomy + PricePremium, data=airline.df, diagonal="histogram")

COrrelation

    options(digits=2)
    cor(airline.df$PitchDifference, airline.df$WidthDifference)
## [1] 0.76

The correlation between pitch difference and width difference was found to be 0.76

Corrgram

    library(corrgram)
corrgram(airline.df, order=TRUE, lower.panel=panel.shade, upper.panel=panel.pie, text.panel=panel.txt, main="Corrgram of airlines intercorrelation")

Correlation Test

cor.test(airline.df$PitchEconomy, airline.df$PriceEconomy)
## 
##  Pearson's product-moment correlation
## 
## data:  airline.df$PitchEconomy and airline.df$PriceEconomy
## t = 8, df = 500, p-value = 3e-16
## alternative hypothesis: true correlation is not equal to 0
## 95 percent confidence interval:
##  0.29 0.45
## sample estimates:
##  cor 
## 0.37

Since p value is less than 0.05 the correlation is statistically significant

Hypothesis - The average price of Economy is less than the average price of Premium Economy seats

    t.test(airline.df$PriceEconomy, airline.df$PricePremium)
## 
##  Welch Two Sample t-test
## 
## data:  airline.df$PriceEconomy and airline.df$PricePremium
## t = -7, df = 900, p-value = 2e-11
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -667 -369
## sample estimates:
## mean of x mean of y 
##      1327      1845

Since the p value was found to be 2e-11 we cannot reject the null hypothesis.

Hypothesis - Greater the duration of the flight, more expensive the price of the ticket

    t.test(airline.df$PriceRelative,airline.df$FlightDuration)
## 
##  Welch Two Sample t-test
## 
## data:  airline.df$PriceRelative and airline.df$FlightDuration
## t = -40, df = 500, p-value <2e-16
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -7.4 -6.8
## sample estimates:
## mean of x mean of y 
##      0.49      7.58

Since the p value is <2e-16 the null hypothesis cannot be rejected

Linear Regression

    model.lm = lm(PriceRelative~PitchDifference + WidthDifference + FlightDuration, data= airline.df)

     summary(model.lm)
## 
## Call:
## lm(formula = PriceRelative ~ PitchDifference + WidthDifference + 
##     FlightDuration, data = airline.df)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -0.7482 -0.2837 -0.0603  0.1645  1.1572 
## 
## Coefficients:
##                 Estimate Std. Error t value Pr(>|t|)    
## (Intercept)     -0.25490    0.08885   -2.87  0.00431 ** 
## PitchDifference  0.05475    0.01567    3.49  0.00052 ***
## WidthDifference  0.12997    0.02336    5.56  4.5e-08 ***
## FlightDuration   0.02160    0.00509    4.24  2.7e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.38 on 454 degrees of freedom
## Multiple R-squared:  0.288,  Adjusted R-squared:  0.283 
## F-statistic: 61.1 on 3 and 454 DF,  p-value: <2e-16

Since p value is less than 2e-16 it is statistically significant

Beta Coefficients

    model.lm$coefficients
##     (Intercept) PitchDifference WidthDifference  FlightDuration 
##          -0.255           0.055           0.130           0.022