Using FORMULA-type questions in Moodle
Importance: This feature helps the faculty by reducing the evaluation time and inspires students to learn the concept thoroughly. The faculty can use Moodle to evaluate every step of the student's solution. The students come to know exactly at what step they went wrong, that too, instantly. They can be given multiple attempts to encourage them to rectify their mistakes. This inspires real learning. For example, see the evaluation results of a single student below
This level of evaluation can be done almost instantly and the error tolerance can be adjusted retrospectively and regraded in negligible time.
If you wish to try the above problem, download "Formula Question on Centroid" of the following .xml file and import into your moodle question bank.
How it works? The software gives the same question but with different input values (random numbers) for each student. So, each student has to solve a different problem. The random numbers can be selected to be within the range set by the examiner (faculty). The answer entered by each student will be auto-evaluated by comparing it with the program-generated solution. The figures below show the view of two different students
Warning: Moodle formula type question involves some simple programming
Moodle is an open source LMS (Learning Management System). You can access it from here.
After using the login button in the top right corner, you can login to the Moodle LMS. If your Moodle coordinator has created courses in which you are enrolled as a Teacher, you can start setting the FORMULA-type question.
.png)
Then you need to create the variables that need to change from student to student. These variables and their name & range are to be defined under variables as shown below. Note that, the range of variable P is from 100 to 200 at an interval of 10. Similarly, the range of variable w varies from 10 to 30 at an interval of 5.
Now the variables are to be used to calculate the correct solutions. This can be done using Moodle functions and operators as shown below. These calculations are to be written under Global Variables. For more functions and operators refer to this link. The list is also given at the end of this post.
After calculating the correct answers for various stages of the solution, we need to describe the question to the students as shown below. Note that we should enclose the variables in curly braces {}, so that the software replaces that field with random values from that variable range
The intermediate parts of the answer can be described in CLEAR manner along with units and sign (+ or -) as shown below. A tabular format is not always needed. Note that the positions where the solution is to be entered is written as {#1}, {#2}, and so on. At these locations, text box(es) will be displayed for the students to enter their answers.
Then we need to set the marks for each answer, the variable that gives the correct answer and the tolerance for the accuracy of the answer. In the figure below, the marks for Part 1 of the answer is assigned '1'. Usually for Part 1 the placeholder name will be #1. The part's text is left blank, as there is no need (in this case) to describe the part further. Click on the '?' mark to know more about each feature. You can also request the student for two or more numbers in a single part!!. The answer type is selected as a numerical formula. The (global) variable giving the CORRECT answer is M1 for this part of the question. This is given as Answer. The grading criteria is set to Absolute error less than 1. You can also give relative error tolerance. 
In similar manner, other parts of the solution are described. You will have to use 'Blanks for 2 more parts' button at the bottom to add more parts to the solution.
In the above example, the correct answer is dV and the student response is _0. (Note that the student response is always denoted by _0). The relative error is abs(dV - _0)/abs(dV). If the relative error is less than 0.05, then the student should get full ONE mark. If the relative error between the correct answer (dV) and the negative of student response (-_0) is less than 0.05, then the student's answer is correct within the limit, but the sign is wrong. Such student should get ,say, 80% of the marks. So, the grading criteria is written as max(myerr1, 0.8*,myerr2)
Close the preview, save the question and go back to the question bank. Preview of the question can be accessed from the question bank also. You can also edit the question, duplicate the question, etc 
List of operators that can be used in MOODLE
After using the login button in the top right corner, you can login to the Moodle LMS. If your Moodle coordinator has created courses in which you are enrolled as a Teacher, you can start setting the FORMULA-type question.
The usual procedure is to create a question in the question bank, and then add that question to a quiz or assignment, etc. So, we will go to the question bank to add this question
.png)
Then we need to create the question as shown below
Then select the FORMULA-type question, and ADD to the question bank as shown below
Give a suitable name to the question, so that you can find the question among the hundreds of questions (that you might be having in your question bank). You can also create categories and add questions within the category, instead of creating the question in the default category.
Then you need to create the variables that need to change from student to student. These variables and their name & range are to be defined under variables as shown below. Note that, the range of variable P is from 100 to 200 at an interval of 10. Similarly, the range of variable w varies from 10 to 30 at an interval of 5.
After calculating the correct answers for various stages of the solution, we need to describe the question to the students as shown below. Note that we should enclose the variables in curly braces {}, so that the software replaces that field with random values from that variable range
The intermediate parts of the answer can be described in CLEAR manner along with units and sign (+ or -) as shown below. A tabular format is not always needed. Note that the positions where the solution is to be entered is written as {#1}, {#2}, and so on. At these locations, text box(es) will be displayed for the students to enter their answers.
In similar manner, other parts of the solution are described. You will have to use 'Blanks for 2 more parts' button at the bottom to add more parts to the solution.
If you wish to give some credit (say 80% marks) to answers which differ from correct answers ONLY in the sign, then do as follows.
In the above example, the correct answer is dV and the student response is _0. (Note that the student response is always denoted by _0). The relative error is abs(dV - _0)/abs(dV). If the relative error is less than 0.05, then the student should get full ONE mark. If the relative error between the correct answer (dV) and the negative of student response (-_0) is less than 0.05, then the student's answer is correct within the limit, but the sign is wrong. Such student should get ,say, 80% of the marks. So, the grading criteria is written as max(myerr1, 0.8*,myerr2)
Finally, save changes to go back to the question bank. If you press, 'Save changes and continue editing', you will stay in the edit-question mode, and will not go back to question bank. If you press cancel, all changes will remain UNSAVED. You can also see the PREVIEW of the question. This gives a view of how the question will be displayed to the student.
The preview of the above question is as follows
You can use the "Fill in correct responses" button below to see the correct responses. You have to check those responses thoroughly.
Hope you find the post helpful. Please leave comments for my inspiration and for improvement of the blog post.
For more information and advanced settings check the following links
