For this question, please use dec_data_modified.csv and download it by right click and save as.  Please construct a training data set and a testing data set by using 80% and 20% of the master data, respectively. To ensure the replicability of the exercise, please set the random seed to 1.  What is the number of observations assigned to the training data?

A linear regression is used for all of the following except one. Which one is not a valid use of  linear regression?

Suppose you want to plot price and quantity, and you want to place price in the vertical axis and quantity in the horizontal axis. Which command would accomplish this task?

For this question, please use dec_data_modified.csv and download it by right click and save as.  Fit the classification tree to the training data using “rpart” as we did in homework 5. To ensure the replicability of the exercise, please set the random seed to 1. What is the accuracy using the fitted tree and the testing data?

Analyze the PC manufacturing industry in the world using Porter’s five-forces model. Internal rivalry is

Analyze the Windows PC manufacturing industry in the world using Porter’s five-forces model. The pressure from buyer power is

Which of the following statements about common software architecture styles is not true?

Mark the correct code for the following DCD.  

The Santa Workshop Gift Tracker helps Santa’s workshop manage holiday gift production. All system users have an account with a unique ID, name, and email. Elves log in to start gift requests, submit gift builds, and view workshop statistics. A Gift Request is created for a specific child and includes a gift type and priority. Elves may submit multiple Gift Builds for a request. Each gift build belongs to exactly one request, and if a gift request is deleted, its builds are also removed. Gift requests are grouped into Toy Categories (e.g., Educational, Outdoor, Plush). Categories exist even if they have no gift requests, and a request may belong to multiple categories. When a gift build is submitted, the system evaluates it using a separate quality-checking service. After a request is prepared for delivery, the system sends a QR code confirmation to the user through an external messaging service. Given the above scenario, which relationships best fill in the blanks in the diagram? Use the component options above to answer the question.

Unlike a Domain Model, which of the following properties must be explicitly defined for attributes and methods in a Design Class Diagram (DCD) to make it implementation-ready?