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Distribution of Chaos Scroll Results

General MapleStory Forum Talk about MapleStory in general

XcoldshadowX Level 22 Windia


Having gotten my 5 year old character to level 200 I'm ready to leave Maplestory behind and move on. However, before I leave I'd like to answer a question that I've pondered over for a while: How are chaos scroll results determined? Most people assume that chaos scroll results are uniform; that there is an equal probability of obtaining each change. However, my experience using chaos scrolls leads me to believe that the results may be approximately normally distributed; the chance of getting a +1 is greater than the chance of getting a +2, +2 greater than +3, ect.

Probability Distributions

The two distributions that I will be focusing on in this experiment are the [url=]uniform distribution[/url] and the [url=]normal distribution[/url].

The uniform distribution is exactly what it sounds like; every outcome has the same probability of occurring. The rolling of a die is an example of a uniform distribution; each outcome of the die has an equal probability of occurring (1/6). If you roll the die many times, you will find that each result appeared an approximately equal number of times. The outcomes will be distributed approximately uniformly link

The normal distribution is a distribution in which the probability of an event decreases as you further deviate from an expected result. For this you can picture the rolling of two dice and taking their sum (assuming each die is independent, which is a safe assumption). There is only one way to get a sum of 2 (1 & 1) or 12 (6 & 6), but multiple ways to get a sum of 3 (1 & 2|2 &1) , a sum of 7 (1&6|2&5|3&4|4&3|5&2|6&1 ). Therefore, you'd expect to get a sum of 7 more than you'd expect to get a sum of 2 or a sum of 12. Here is the [url=]theoretical distribution[/url] of summing dice results; each probability is determined by dividing the possible outcomes for each event by the total number out outcomes. For a sum of 2 this is 1/36; for a sum of 7 this is 6/36. If you were to roll a die many times you'd expect the results to resemble this. Notice that the distribution is symmetrical; the probability of getting an 8 is the same as the probability of getting a 6. Also notice the bell-like shape of the distribution. This is characteristic of normal distributions and is known as a Bell Curve.

Chaos Scrolls

Chaos scrolls have the ability to make each stat better or worse by a maximum of 5 points. The possible results of a chaos scroll on a stat are: +5, +4, +3, +2, +1, 0, -1, -2, -3, -4, -5 (for +hp/mp multiply each number by 10). If chaos scroll results are normally distributed then each outcome has a probability of 1/11 of happening. If the results are normally distributed then each outcome has an unknown probability. No change would be the most likely, +-1 would be the next most likely, ect.


-Each stat on an item is independent from other stats
-Chaos scroll results are independent from each other
-All stats change in the same way (int and mdef have the same probability distribution)
-Chaos scroll changes do not depend on the quantity of a stat on an item as long as the stat exists on the item (a+10 stat changes with the same probability distribution as a +180 stat)


-The chaos scroll must be successful
-A stat must be 5 or greater before the chaos scroll(50 or greater for hp/mp) for the result to be recorded. If a stat is less than 5 and a chaos scroll takes the stat away, then I am left with an ambiguous result (was it -5 or -4?). To eliminate this, I will simply ignore the change to a stat that is 4 or less and consider this stat invalid for the current chaos scroll. Since I am assuming that the quantity of a stat does not affect a chaos scroll I've eliminated the issue.


-I will buy many chaos scrolls, hopefully well over 100.
-I will chaos items that will give me many valid results. The items that I am currently focusing on are lvl 70 maple hats (10 valid stats), targa helms, scar helms, and zhelms (8 valid stats)
-The results will be recorded


-After 81 valid changes this is the graph that was produced.
I need to wait for some of my stuff to sell before I can do more. This is a work in progress and I will try to update this thread as much as I can until the results are satisfactory.

-After 248 valid changes this is the graph that was produced.
The Bell Curve is becoming apparent; most values are clustered towards the center of the graph. It's almost obvious at this point that the probability of having a stat change by 5 is not the same as the probability of a stat changing by 1. I'd still like to keep going with this.

If you have any questions or comments, or if you see an error anywhere in my post (a careless definition, spelling error, ect), please let me know. If you'd like to contribute then please post your raw data in the comments.

*NEW* Contributing

If you'd like to contribute data, please take a screenshot of the item after each successful chaos scroll and place it on an image hosting site such asimgur as an album. Here's an example


EDIT: Added sentences about the Bell Curve
Posted: January 2012 Permalink


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biyomon3 Level 162 Bellocan Battle Mage 4
I like how there's a 0% chance of +5 right now.
Jan 02 2012
XcoldshadowX Level 22 Windia
I like how there's a 0% chance of +5 right now. [/quote]

I've only seen one +5 so far out of about 120 changes, but I couldn't use it because it happened on an invalid stat.
Jan 02 2012
This is very interesting. You're right, everyone always thinks that there's a 1/11 chance of getting each stat. The second graph is a very strong argument against chaos scrolls having a uniform distribution. I still think you need more data, but this is a great start!
Jan 02 2012
sadending Level 200 Windia Night Lord
I can't believe you spent all this money on chaos scrolls, when people like Sublimisity can't even buy pots for himself, why don't you do something better with the money like donating it to SUBLIMISITY.
Jan 02 2012
Just as a reminder... People on basilmarket pay attention to threads they can flame... This is thought out and intelligent! So pretty much no flaming can/will occur... With that being said, this will not be on the front cover of the basil threads for a long time unless someone with as much intelligence as yourself can properly debate this topic with you. I do applaud you for the amount of work put into this theory
Jan 02 2012
It's disappointing to observe that there's a higher rate that a larger stat number will be taken away rather than adding. How can I explain myself... even when the scroll passes and adds a small amount of stat, there's a better chance that if the scroll would pass again, the stat would be taken away. Lol. Thank you for making this graph, man. Now I wonder if the other Chaos Scrolls work the same...
Jan 02 2012
I have a question about chaos scrolls: Once it degrades your item (takes away stats) will it always degrade it? Or do you still have a chance for it to upgrade?
Jan 02 2012
XcoldshadowX Level 22 Windia
I have a question about chaos scrolls: Once it degrades your item (takes away stats) will it always degrade it? Or do you still have a chance for it to upgrade?[/quote]

Each scroll is independent of the previous scroll. During the course of 9 chaos scrolls I had the luk of a zhelm quickly go down to 10, slowly rise up to 18, then down to 13 on the last scroll.
Jan 02 2012
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