Reference no: EM131407276

Description

In the previous assignment you had to mark a multiple-choice exam for 27 students. marks_assignment1.tsv contains the marks of the students.

a) Read the marks from the marks_assignment1.tsv into a data.frame called marks.

b) Write a function called getDegree, which takes as input a mark and returns the degree the student achieved:
- "1st" for marks higher or equal to 70
- "2:1" for marks higher or equal to 60 and lower than 70
- "2:2" for marks higher or equal to 50 and lower than 60
- "3rd" for marks higher or equal to 40 and lower than 50
- "failed" for marks lower than 40
Hint: One of the many ways to do this would be with if statements.

c) Compute the degree for each student and add a new column to the data.frame called degree.

d) Create a plot and save it to a pdf file called degree_statistics.pdf. The plot comprises of two panels on one row. The first panel is a bar graph with the number of students that obtain each degree and the second panel is a pie chart of the same information. Add titles, labels, a letter to identify each panel ("A" and"B") in the top left corner of the panel (outside the plot). Change the colour of the bar plot to black. Used a different colour for each degree: blue for"1st", green for "2:1", yellow for "2:2" orange for "3rd" f and red for "failed"

e) Create a histogram with all the marks and save it to a pdf file called marks_hist.pdf. Add titles and labels to the plot.

f) Split the marks based on the degree and create a box plot for the marks of each degree (you will have a box plot with 5 boxes, one for each of the degrees). Used a different colour for each degree (same as point d).

Change the y-axis to display horizontally only the levels: "0%", "40%", "50%", "60%", "70%" and "100%". Save this plot into a pdf file called marks_boxplot.pdf.

g) Order the data.frame based on the marks in decreasing order. Split the data.frame based on the degree. Plot using vertical bars the marks of every student that obtained a "first".

Hint: look at the type argument of the plot function.

Using a for loop and lines plot the rest of the marks grouped by degrees. Keep the same colour scheme from task d. Add a legend on the top right corner with the degrees and the colour schemes. Add titles and labels to the plot. On x-axis, plot the student id vertically. Add dotted gray lines delimiting the degrees. Change the y-axis as in task f. Save this plot to a pdf file marks_by_degree.pdf

Attachment:- marks_assignment1.rar