代做CS617程序、代写R编程语言

日期：2025-07-18 09:50

Project 5 Assignment

Score is 30 points (10 poinst each question).

Question 1

Exploring and Analyzing Data Using R Functions

Objective

This assignment will assess your ability to:

• Import and explore a dataset in R

• Apply basic R functions for data manipulation and analysis

• Generate summary statistics and visualizations

• Write clean, well-commented R code

Instructions

1. Dataset Selection

Use the built-in dataset mtcars in R for this assignment.

2. Tasks

(A) Data Exploration

o Display the first 6 rows of the dataset using an appropriate R function.

o Use str(), summary(), and dim() functions to explore the dataset.

o Identify the variable with the highest mean value using R code.

(B) Data Manipulation

o Create a new variable efficiency as mpg/hp. Add this as a new column.

o Filter the dataset to include only cars with mpg > 20.

o Sort the dataset in descending order based on efficiency.

(C) Data Analysis

o Calculate the mean, median, and standard deviation of mpg, hp, and wt.

o Use the aggregate() function to compute the average horsepower (hp)

grouped by the number of cylinders (cyl).

o Create a bar plot to compare the average mpg by cylinder count.

(D) Code Presentation (20 marks)

o Your R script should include meaningful comments.

o Use clear, readable formatting.

o Include a brief summary (3–5 sentences) of your findings in a comment block

at the top.

Question 2

R Programming Assignment: User-Defined Functions

Assignment: Analyzing Student Grades

Scenario: You've been given a dataset of student scores for three different assignments

(Assignment 1, Assignment 2, and Final Exam). You need to create R functions to perform

some basic analysis on these scores.

Instructions:

1. Create a function calculate_average_score:

o This function should take a numeric vector of scores as input.

o It should return the average (mean) of these scores.

o Handle the case where the input vector might contain NA values by removing

them before calculation.

2. Create a function assign_grade_category:

o This function should take a single numeric score (representing an average

score) as input.

o It should return a character string representing the grade category based on

the following criteria:

▪ 90-100: "Excellent"

▪ 80-89: "Good"

▪ 70-79: "Satisfactory"

▪ 60-69: "Pass"

▪ Below 60: "Fail"

o Assume the input score will be between 0 and 100.

3. Demonstrate your functions:

o Create a sample data frame named student_scores with the following data:

Student Assignment1 Assignment2 FinalExam

Alice 85 92 88

Bob 70 NA 75

Carol 95 88 90

David 55 60 50

o Export to Sheets

o Using your calculate_average_score function, add a new column to

student_scores called OverallAverage which contains the average of

'Assignment1', 'Assignment2', and 'FinalExam' for each student.

o Using your assign_grade_category function, add another new column to

student_scores called GradeCategory based on the OverallAverage score.

o Print the final student_scores data frame.

Question 3

R Assignment: Calculating the Area of a Circle

Objective: Create a user-defined function in R that calculates the area of a circle given its

radius.

Instructions:

1. Define a function named calculate_circle_area that takes one argument: radius.

2. Inside the function, use the formula for the area of a circle: Area=pi\*radius2.

3. The function should return the calculated area.

4. Test your function by calculating the area of a circle with a radius of 5 and another

with a radius of 10.

5. Print the results clearly.

Submission Guidelines

• Submit an .R script file named lastname_firstname_assignment.R.

• Make sure your code runs without errors.

• Use only base R and built-in datasets/functions (no external libraries).