Full Mathematical Power In Calculated Questions Through Spreadsheets

Full Mathematical PowerIn Calculated QuestionsThrough Spreadsheets

Moodle Research 2013

[email protected] @hiramglows

Context• Artesis Plantijn University College Anwerp

• 1st year Professional Bachelors Business Studies

a very heterogeneous group

• Applied Statistics

– collaborate and peer teach live online.

– self-pacing, enabling faster students to advance and help slower students

– spreadsheets to solve the exercises.

– gather learning content from the web.

first line electronic tutor.

[email protected] @hiramglows

Calculated Questions in Moodle• Example:

Calculate the area of a rectangle with a base of {base}cm and a height of {height}cm.

• 3 parts:

– Wildcards: {base} & {height}

– Formula: {base} * {height}

– Data Set: {base} = 8 {height}=4{base} = 2 {height}=7{base} = 5 {height}=3… …

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Published Calculated Questions• Moodle merges the question text with values from

the data set:

Calculate the area of a rectangle with a base of 8cm and a height of 4cm.

• Moodle calculates the result using a given formula and the published values:

Answer: 8 * 4 = 32

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Very powerful, but…• Moodle understands about 42 mathematical

functions ranging from “+” to “tanh”

• Limits?we managed to get a 1171 characters long formula with nine variables working generating an answer that looks like

“4 years, 7 months and 15 days”

• But…What if you would like to create formulas using statistical functions?

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Example: The Binomial Distribution

• Calculate the chance of more than 1 but less than 7 successes given there are 8 trials and the chance of success is 18%.

• With a spreadsheet this is easily solved:

BINOMDIST(6 , 8 , 0.18 , true)-BINOMDIST(1 , 8, 0.18 , true)

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The solution: Moodle XML• Moodle allows EXPORT & IMPORT of XML files

• XML = eXtensible Markup Language = markup language defining a set of rules for encoding documents in a format that is both human-readable and machine-readable.

<question type="calculated"><name><text>bi_tires</text>

</name><questiontext format="html"><text>Sample</text>

</questiontext>

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Trick {answer}• VBA: extract content from a spreadsheet and

translate into XML

• Introduce new wildcard {answer} and give it the value calculated by a formula of your choice.

PROBLEM

You need to include [answer} in the question text!

(and use {answer} in the formula specified in the definition of the calculated question)

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• Hide:You can use HTML tags in the question text and thus hide text with comment tags

<!– hidden text -->

Be aware that hidden text is very visible in the page source code

• Camouflage:Place a random set of random numbers in before and after the correct answer

Hide and Camouflage

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Result

Expect that somebody will explore the page source code.

And if this is not enough, there are more easy tricks to hide away the correct answer.

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CQ4M Generator• Download this spreadsheet from

https://sites.google.com/site/cq4mgenerator/

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Regions

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Calculation of the correct answer andalternatives

Definition and

preparationof all usedvariables

(wildcards)

Dataset:All values for the

wildcards, answers are multiplied with a ‘disguising’ factor

Camouflaging

Moodle Question Definition

Macro assigned buttons

Moodle Formula Definition

Steps

1. Question Name

2. Category Name

3. Question Text

4. Default Grade

5. Formulas

6. Wildcards

7. Preparation

8. Work Area

9. XML

[email protected] @hiramglows

• Google Group CQ4M Generatorhttps://groups.google.com/forum/#!forum/cq4m-generator

• Google Site CQ4M Generatorhttps://sites.google.com/site/cq4mgenerator/

• Mail, [email protected], @hiramglows

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Comment! Share!

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Thank you