Question

E-commerce and online shopping are creating a rapidly growing demand for parcel

delivery services. The key factors of customers’ satisfactions are both the speed and

frequency of delivery which require more efficient flow of parcels through the

transportation. To help improve its transportation network performance, a private

postal service in North America conducted a survey to analyze the relationship

between delivery results (1: on-time and 2: late) and transportation mode (1: regular,

2: express, and 3: weekend delivery). A sample of 70 deliveries was asked from the

sale department. Data can be found in the Excel file AS4.XLSX (Ecom) in the Excel

directory. Do these data allow us to infer that the delivery results are affected by the

transportation mode (5% significance)?

Delivery result
Transportation mode	Delivery Result
Express	On-Time
Weekend Delivery	Late
Express	On-Time
Regular	On-Time
Regular	On-Time
Weekend Delivery	On-Time
Weekend Delivery	Late
Weekend Delivery	On-Time
Regular	On-Time
Express	Late
Express	Late
Weekend Delivery	Late
Express	On-Time
Regular	On-Time
Regular	On-Time
Regular	On-Time
Regular	On-Time
Express	On-Time
Weekend Delivery	Late
Regular	On-Time
Regular	On-Time
Regular	On-Time
Weekend Delivery	Late
Regular	On-Time
Regular	On-Time
Weekend Delivery	On-Time
Weekend Delivery	Late
Regular	On-Time
Regular	On-Time
Weekend Delivery	On-Time
Express	Late
Express	On-Time
Regular	On-Time
Regular	On-Time
Express	On-Time
Weekend Delivery	Late
Weekend Delivery	Late
Weekend Delivery	Late
Regular	On-Time
Regular	On-Time
Regular	On-Time
Regular	On-Time
Weekend Delivery	Late
Regular	Late
Regular	On-Time
Express	Late
Weekend Delivery	Late
Regular	On-Time
Regular	On-Time
Express	On-Time
Express	Late
Weekend Delivery	Late
Express	Late
Regular	On-Time
Regular	On-Time
Weekend Delivery	On-Time
Express	Late
Regular	On-Time
Weekend Delivery	On-Time
Weekend Delivery	On-Time
Weekend Delivery	Late
Weekend Delivery	Late
Regular	On-Time
Regular	On-Time
Weekend Delivery	On-Time
Express	On-Time
Express	On-Time
Weekend Delivery	On-Time
Express	On-Time
Regular	On-Time

Answer 1

This is chi-square test of independence

install.packages("readxl")
library(readxl)
delivery = read_excel("../Tutoring/Software/random data/delivery.xlsx")
tbl <- table(delivery$`Transportation mode`,delivery$`Delivery result`)
tbl
chisq.test(tbl)

since p-value = 0.0000277 < alpha(0.05)

hence we reject the null hypothesis

we conclude that there is sufficient evidence that the delivery results are affected by the transportation mode