Lab Assignment 5 Instructions

In this assignment, you will use data from the Midterm Exam in the Fall Semester of 2023. The data file is named “Data205_2023Fall_Midterm.csv” as you can see in this RStudio Cloud project. There are two variables in this data set.

The “lab” variable shows which DATA 205 Lab each student is attending. There are three labs: A, B, and D.

The “midterm” variable shows each student’s midterm exam score, which has been rescaled between 0 to 100 points.

Here is the R code to import the data into a R data frame named “df”:

df <- read.csv("Data205_2023Fall_Midterm.csv")

Exercise 1 (6 Points):

Write R code below to find out:

  1. the number of students who took the midterm exam; (2 points)
  2. the mean of the exam scores; (2 points)
  3. the median of the exam scores. (2 points)

Note that in addition to show your R code and output, you also need to explicitly report the number of students, the mean, and the median in words/text. Otherwise, you will only receive partial credits.

summary(df$midterm)
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##   20.00   47.75   57.00   56.40   63.00   87.00

Answer: There were 58 students who took the exam. The mean is 56.40 and the median is 57.

Exercise 2 (2 Points):

Write R code here to create a histogram of the exam scores.

hist(df$midterm)

Exercise 3 (4 Points):

Write R code to create boxplots of the midterm scores for students in different Labs (2 points).

boxplot(df$midterm ~ df$lab)

Based on the boxplots, do you think whether or not there is any difference in students’ midterm exam scores across the three Labs? (2 point).

Answer: According to the box plots, lab group A has the widest range of test scores, group B has the lowest peak in test scores, and group C has the largest median of test scores, among other observations that distinguish the three lab groups.

Submitting Your Assignment

Please knit your Markdown document into a HTML file and publish it on RPubs (see Lab 5 slides), and submit the link to your published webpage on the Blackboard.