Assignment 6

We will analyze the following chart to compare the arrival delays for the two airlines: Alaska and AM West.

library(tidyr)
library(dplyr)
library(magrittr)
library(knitr)
library(ggplot2)

# Read the csv file 
airline <- read.csv(file = "airline_arrivals.csv", stringsAsFactors = FALSE)
kable(airline)

Airline	ArrivalStatus	Los.Angeles	Phoenix	San.Diego	San.Francisco	Seattle
ALASKA	on time	497	221	212	503	1841
ALASKA	delayed	62	12	20	102	305
AM WEST	on time	694	4840	383	320	201
AM WEST	delayed	117	415	65	129	61


# Make table from wide to long and get delayed rows
airline_delayed <- airline %>%
  gather("ArrivalCity", "Flights", 3:7) %>%
  arrange(Airline) %>%
  filter(ArrivalStatus == "delayed") %>%
  select(Airline, ArrivalCity, Flights)


# Get on time rows for percentage calculations
airline_ontime<- airline %>%
  gather("ArrivalCity", "Flights", 3:7) %>%
  arrange(Airline) %>%
  filter(ArrivalStatus == "on time") %>%
  select(Airline, ArrivalCity, Flights)

# Add DelayRate column
airline_delayed["DelayRate"] <- round(airline_delayed$Flights / (airline_delayed$Flights+airline_ontime$Flights),2)
kable(airline_delayed)

Airline	ArrivalCity	Flights	DelayRate
ALASKA	Los.Angeles	62	0.11
ALASKA	Phoenix	12	0.05
ALASKA	San.Diego	20	0.09
ALASKA	San.Francisco	102	0.17
ALASKA	Seattle	305	0.14
AM WEST	Los.Angeles	117	0.14
AM WEST	Phoenix	415	0.08
AM WEST	San.Diego	65	0.15
AM WEST	San.Francisco	129	0.29
AM WEST	Seattle	61	0.23


# Plot airlines by number of delays
p <- ggplot(airline_delayed, aes(fill=Airline, x=ArrivalCity, y=Flights))
p + geom_bar(position="dodge", stat="identity") + labs(title = "Delay in Numbers")

From looking at number of delays chart above, it appears AM West has more delays than Alaska 80% (4/5) of the time. Phoenix being the number one and that is because more flights land there than Alaska airlines.

# Plot airlines by percentage of delays
p2 <- ggplot(airline_delayed, aes(fill=Airline, x=ArrivalCity, y=DelayRate))
p2 + geom_bar(position="dodge", stat="identity")  + scale_fill_brewer(palette="Set2") + labs(title = "Delay in Percentages")

Looking at the rate of delays in both airlines, again AM West has more delays, however this time it is at all destinations, including Seattle!
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Assignment 6

Puneet Auluck

October 2, 2015