Read data on airlines

airline<-read.csv(file="SixAirlinesDataV2.csv")

discribing statistics

attach(airline)
library(psych)
describe(airline)
##                     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

discribing PriceEcomony and PricePremium

library(psych)
describe(airline$PriceEconomy)
##    vars   n    mean     sd median trimmed     mad min  max range skew
## X1    1 458 1327.08 988.27   1242  1244.4 1159.39  65 3593  3528 0.51
##    kurtosis    se
## X1    -0.88 46.18
describe(airline$PricePremium)
##    vars   n    mean      sd median trimmed     mad min  max range skew
## X1    1 458 1845.26 1288.14   1737 1799.05 1845.84  86 7414  7328  0.5
##    kurtosis    se
## X1     0.43 60.19
describe(airline$PriceRelative)
##    vars   n mean   sd median trimmed  mad  min  max range skew kurtosis
## X1    1 458 0.49 0.45   0.36    0.42 0.41 0.02 1.89  1.87 1.17     0.72
##      se
## X1 0.02

Histogram for PriceEconomy and PricePremium

hist(airline$PriceEconomy, 
     breaks=18, 
     col="gray", 
     xlab="PriceEconomy", 
     main="Histogram for PriceEconomy")

hist(airline$PricePremium, 
     breaks=18, 
     col="gray", 
     xlab="PricePremium", 
     main="Histogram for PricePremium")

Boxplot of Pitch Economy

boxplot(PitchEconomy,horizontal = TRUE,main="Pitch economy",xlab="inches",col = "blue")

Boxplot of Pitch Premium

boxplot(PitchPremium,horizontal = TRUE,main="Pitch Premium",xlab="inches",col = "blue")

boxplot of seat Economy

boxplot(SeatsEconomy,horizontal = TRUE,main="Seats economy",xlab="Number of seats",col = "yellow")

boxplot of seat Premium

boxplot(SeatsPremium,horizontal = TRUE,main="Seats Premium",xlab="Number of seats",col = "yellow")

plot of PriceEconomy v/s TravelMonth

library(car)
## 
## Attaching package: 'car'
## The following object is masked from 'package:psych':
## 
##     logit
scatterplot(x=airline$TravelMonth, y=airline$PriceEconomy,main="scatterplot of TravelMOnth vs PriceEcomony",xlab ="TravelMonth",ylab="PriceEconomy" )

plot of PricePremium v/s TravelMonth

library(car)
scatterplot(x=airline$TravelMonth, y=airline$PricePremium,main="scatterplot of TravelMonth vs PricePremium",xlab ="TravelMonth",ylab="PricePremium" )

## [1] "367" "369" "368"

scatterplotmatrix for finding dependence of PriceEconomy on the factors like TravelMonth,FlightDuration and SeatEconomy

scatterplotMatrix(formula = ~ TravelMonth + FlightDuration + SeatsEconomy +PriceEconomy, cex=0.5,
                       data=airline, diagonal="histogram")

scatterplotmatrix for finding dependence of PricePremium on the factors like TravelMonth,FlightDuration and SeatEconomy

scatterplotMatrix(formula = ~ TravelMonth + FlightDuration + SeatsPremium +PricePremium, cex=0.5,
                       data=airline, diagonal="histogram")

corrogram of the data set of airlines

library(corrgram)
corrgram(airline, order=FALSE, 
         lower.panel=panel.shade,
         upper.panel=panel.pie, 
         diag.panel=panel.minmax,
         text.panel=panel.txt,
         main="Corrgram of airline intercorrelations")

T-Test

t.test(PriceEconomy,PricePremium)
## 
##  Welch Two Sample t-test
## 
## data:  PriceEconomy and PricePremium
## t = -6.8304, df = 856.56, p-value = 1.605e-11
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -667.0831 -369.2793
## sample estimates:
## mean of x mean of y 
##  1327.076  1845.258

Regression analysis-Economy class Price

fit <- lm(PriceEconomy~Aircraft+Airline+FlightDuration+PitchEconomy+WidthEconomy+SeatsEconomy+SeatsTotal+IsInternational+TravelMonth)
summary(fit)
## 
## Call:
## lm(formula = PriceEconomy ~ Aircraft + Airline + FlightDuration + 
##     PitchEconomy + WidthEconomy + SeatsEconomy + SeatsTotal + 
##     IsInternational + TravelMonth)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -2062.88  -225.82    82.01   333.89  1295.47 
## 
## Coefficients:
##                                Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                   1403.5686  3343.2395   0.420  0.67482    
## AircraftBoeing                 205.4897    69.0014   2.978  0.00306 ** 
## AirlineBritish               -1488.2293   142.9282 -10.412  < 2e-16 ***
## AirlineDelta                  -750.3835   251.0278  -2.989  0.00295 ** 
## AirlineJet                   -2118.1280   177.5262 -11.931  < 2e-16 ***
## AirlineSingapore             -2013.5367   179.3390 -11.228  < 2e-16 ***
## AirlineVirgin                -1261.1819   150.4913  -8.380 7.09e-16 ***
## FlightDuration                 102.9963     9.8625  10.443  < 2e-16 ***
## PitchEconomy                    -0.1632    88.2251  -0.002  0.99852    
## WidthEconomy                   -46.5380   101.3161  -0.459  0.64622    
## SeatsEconomy                    -8.2380     4.4291  -1.860  0.06355 .  
## SeatsTotal                       6.9760     4.1363   1.687  0.09240 .  
## IsInternationalInternational  1236.9651   274.4896   4.506 8.45e-06 ***
## TravelMonthJul                  99.2021    77.3651   1.282  0.20042    
## TravelMonthOct                 -44.1857    65.7197  -0.672  0.50172    
## TravelMonthSep                   3.2497    65.5355   0.050  0.96047    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 523.5 on 442 degrees of freedom
## Multiple R-squared:  0.7286, Adjusted R-squared:  0.7194 
## F-statistic: 79.11 on 15 and 442 DF,  p-value: < 2.2e-16

Regression analysis-Premium class Price

fit <- lm(PricePremium~Aircraft+Airline+FlightDuration+PitchPremium+WidthPremium+SeatsPremium+SeatsTotal+IsInternational+TravelMonth)
summary(fit)
## 
## Call:
## lm(formula = PricePremium ~ Aircraft + Airline + FlightDuration + 
##     PitchPremium + WidthPremium + SeatsPremium + SeatsTotal + 
##     IsInternational + TravelMonth)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -2133.0  -362.5    52.8   348.8  4422.7 
## 
## Coefficients:
##                                Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                  -4447.4061  5618.2846  -0.792  0.42902    
## AircraftBoeing                 249.0832    93.7752   2.656  0.00819 ** 
## AirlineBritish               -1016.4414   145.5283  -6.984 1.06e-11 ***
## AirlineDelta                  -349.9291   562.9812  -0.622  0.53455    
## AirlineJet                   -2101.6561   289.4373  -7.261 1.74e-12 ***
## AirlineSingapore             -2161.7807   273.3757  -7.908 2.12e-14 ***
## AirlineVirgin                 -516.4144   475.7778  -1.085  0.27833    
## FlightDuration                 176.8906    14.2051  12.453  < 2e-16 ***
## PitchPremium                   103.1443   228.7034   0.451  0.65221    
## WidthPremium                    49.0335   225.1650   0.218  0.82771    
## SeatsPremium                     3.0724     6.4245   0.478  0.63272    
## SeatsTotal                      -0.4734     0.7007  -0.676  0.49968    
## IsInternationalInternational   968.1084   727.0516   1.332  0.18369    
## TravelMonthJul                  91.6748   111.8856   0.819  0.41302    
## TravelMonthOct                 -25.8581    95.0397  -0.272  0.78569    
## TravelMonthSep                  -0.8705    94.7890  -0.009  0.99268    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 756.7 on 442 degrees of freedom
## Multiple R-squared:  0.6662, Adjusted R-squared:  0.6549 
## F-statistic: 58.81 on 15 and 442 DF,  p-value: < 2.2e-16

for Price difference

PriceDifference  <- (PricePremium - PriceEconomy)

Regression analysis-Economy class PriceDifference

fit <- lm(PriceDifference~FlightDuration+PitchDifference+WidthDifference+SeatsEconomy+SeatsPremium+SeatsTotal+IsInternational)
summary(fit)
## 
## Call:
## lm(formula = PriceDifference ~ FlightDuration + PitchDifference + 
##     WidthDifference + SeatsEconomy + SeatsPremium + SeatsTotal + 
##     IsInternational)
## 
## Residuals:
##    Min     1Q Median     3Q    Max 
## -869.7 -245.0  -48.1  138.0 3487.1 
## 
## Coefficients: (1 not defined because of singularities)
##                               Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                  -680.2122   136.4176  -4.986 8.80e-07 ***
## FlightDuration                 93.2929     8.1075  11.507  < 2e-16 ***
## PitchDifference                53.2696    32.9336   1.617  0.10647    
## WidthDifference               126.8535    32.0295   3.961 8.69e-05 ***
## SeatsEconomy                   -0.5342     0.3887  -1.374  0.17010    
## SeatsPremium                   16.7787     2.3220   7.226 2.14e-12 ***
## SeatsTotal                          NA         NA      NA       NA    
## IsInternationalInternational -579.0802   179.8990  -3.219  0.00138 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 476.4 on 451 degrees of freedom
## Multiple R-squared:  0.343,  Adjusted R-squared:  0.3343 
## F-statistic: 39.25 on 6 and 451 DF,  p-value: < 2.2e-16

Regression analysis-Premium class PriceDifference

fit <- lm(PriceDifference~FlightDuration+PitchEconomy+WidthEconomy+PitchPremium+WidthPremium+SeatsEconomy+SeatsPremium+SeatsTotal+IsInternational)
summary(fit)
## 
## Call:
## lm(formula = PriceDifference ~ FlightDuration + PitchEconomy + 
##     WidthEconomy + PitchPremium + WidthPremium + SeatsEconomy + 
##     SeatsPremium + SeatsTotal + IsInternational)
## 
## Residuals:
##    Min     1Q Median     3Q    Max 
## -897.9 -228.3  -68.8  120.9 3317.7 
## 
## Coefficients: (1 not defined because of singularities)
##                                Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                  18831.7431  3912.0162   4.814 2.03e-06 ***
## FlightDuration                  83.2522     8.2469  10.095  < 2e-16 ***
## PitchEconomy                  -303.1791    56.8031  -5.337 1.50e-07 ***
## WidthEconomy                  -131.7218    54.5592  -2.414   0.0162 *  
## PitchPremium                  -288.6342    72.3187  -3.991 7.68e-05 ***
## WidthPremium                   149.7156    32.9592   4.542 7.15e-06 ***
## SeatsEconomy                     0.1852     0.4035   0.459   0.6464    
## SeatsPremium                     5.7414     3.0630   1.874   0.0615 .  
## SeatsTotal                           NA         NA      NA       NA    
## IsInternationalInternational   728.8061   310.4695   2.347   0.0193 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 463 on 449 degrees of freedom
## Multiple R-squared:  0.3822, Adjusted R-squared:  0.3712 
## F-statistic: 34.73 on 8 and 449 DF,  p-value: < 2.2e-16

Regression analysis-Relative price

fit <- lm(PriceRelative~FlightDuration+PitchEconomy+WidthEconomy+PitchPremium+WidthPremium+SeatsEconomy+SeatsPremium+SeatsTotal+PitchDifference+WidthDifference)
summary(fit)
## 
## Call:
## lm(formula = PriceRelative ~ FlightDuration + PitchEconomy + 
##     WidthEconomy + PitchPremium + WidthPremium + SeatsEconomy + 
##     SeatsPremium + SeatsTotal + PitchDifference + WidthDifference)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.86549 -0.25418 -0.07713  0.14522  1.34717 
## 
## Coefficients: (3 not defined because of singularities)
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)      6.8912366  1.7209126   4.004 7.27e-05 ***
## FlightDuration   0.0278757  0.0058374   4.775 2.43e-06 ***
## PitchEconomy    -0.2606111  0.0411633  -6.331 5.90e-10 ***
## WidthEconomy    -0.0050452  0.0415730  -0.121   0.9035    
## PitchPremium    -0.0194938  0.0212963  -0.915   0.3605    
## WidthPremium     0.1256658  0.0259356   4.845 1.74e-06 ***
## SeatsEconomy     0.0007934  0.0003168   2.505   0.0126 *  
## SeatsPremium    -0.0076652  0.0019421  -3.947 9.19e-05 ***
## SeatsTotal              NA         NA      NA       NA    
## PitchDifference         NA         NA      NA       NA    
## WidthDifference         NA         NA      NA       NA    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.3689 on 450 degrees of freedom
## Multiple R-squared:  0.3401, Adjusted R-squared:  0.3299 
## F-statistic: 33.14 on 7 and 450 DF,  p-value: < 2.2e-16