Posts

Creating Jipime

Generally, I love tests since they give you the ability to somewhat (but not accurately) gauge yourself

Throughout March to May 2024, I took multiple quasi online IQ tests and learnt the following:

• Nature of questions asked.
• Choice of answers.
• Calculation methods (IQ valuation).

Being inspired by them and realizing that I am blesssed with the power to build, I decided why not just build my personal IQ test and even ask my friends to do it.

Through a little bit of typescript and a dash of tailwind css, I built a simple fun app that tests user's mental capabilities.

Technologies used (doesn't matter):

• Frontend: ReactJS
• Backend: Typescript
• Database: Redis instance (formerly used MongoDb)

How the website works

When you open it and select an age group, it creates a random user ID (hash of the current timestamp). All test scores are stored as an object on a redis instance (chosen due to speed and MongoDb would lag at times). The userID is stored on the browser as a session Cookie so that the test can be done multiple times.

Here is an example:

{
    userID: 2iddjm0d3j9,
    TestOne: 8,
    TestTwo: 4,
    TestThree: 3

}

I only faced two hurdles here: IQ calculation and coming up with questions.

Coming up with questions

I figured out that one of the human brain's default capabilities is binary thinking (yes or no, true or false, potato or tomato), therefore I made sure that the first part of the test would include such. The questions here are geared to make the user lean into trusting their gut thus picking the wong answer (see, i spelt wrong incorrectly but you read it right since you trust your gut).

Since most of my peers grew up with the internet and suffer a small attention spans, I made sure that the first part would be fast and the user would get their results immediately and continues with their activities.

Also, both True and False options are equal (Five questions are true, the other five are false)

The second part also involves binary thinking methods however it is a bit different since it involves questions from mathematics and imagery (not just critical thinking like those from part one).

I mean, look at this sample question (I'm sure you can do it)

Jake needs 16 bottles of water from the store. John can only carry 3 at a time. The minimum number of trips John makes is thus 6?

# True. 
Trip 1 - 3
Trip 2 - 3
Trip 3 - 3
Trip 4 - 3
Trip 5 - 3
Trip 6 - 1 +
---------------
Total - 16

The last part involves vocabulary, idioms and grammar use (My condolences to all Non English speakers, as this part somewhat nullifies your previous efforts).

Explaining the Math used

Out of 10 questions asked, the average user should score only five or seven.

Basic definitions:

• Mean/ average: The most normal thing you ordinarily see.
• Standard deviation: The more one is far from normal, the higher standard deviation is.
• Z score: Number of standard deviations a raw or given score is far or close to the mean

Here is an example:

Let's say the average height of women is 5'4" (64 inches) with a standard deviation of 2 inches. If a woman is 5'6" (66 inches) tall, her z-score is:

z = (66 - 64) / 2 = 1

Now, to calcuate percentile I used the below formula:

(1 + erf(zScore / Math.sqrt(2))) / 2 * 100

The erf gives the area under the normal distribution curve. Generally, the above formula expresses probability as a percentage.

Proceeding to calcuate IQ:

zScore = (rawScore - meanScore) / sdScore

Note:

• zScore: your total tests score out of 29
• meanScore: 100
• sdScore: 15
• starterIQ: +2 if your age range if below 16 and above 60, other ages get 0

Finally:

Math.round(100 + zScore * 15 + starterIQ)

The server sends the percentile and IQ as a JSON object to the frontend therefore delivering results. The percentile is also used to rank the user out of 1000 people.

If you do however have any ideas, please contact me or even submit a PR

THANK you for reading!