Shipwright Archive
Thread: Firespray discs statistics or bad luck?
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ArianSix
Mon Nov 29, 2004 7:45 am
#1
I'm curious about the drop rates others have been getting on firespray discs.
My drop rate has been about 1 disc per 125 items (not RE's but items going in). I currently have 21 discs.
Now the weird part. Of these 21 discs, I have 1 disc 3 and 0 disc 6's. Being that you'd expect roughly a 1:8 chance of getting any disc, you'd think I'd have at least 1full set by now.
On the flip side, I met a SW who was having a hard time getting a 5, so I traded him 2 of them for 2 discs I already had to get him on his way.
So I was wondering... are you guys finding weird statical anamolies like this and are you having a hard time getting any particular discs? (like 6 for me and 5 for that other guy)
Oh, and if any of you Bloodfin SW have an extra disc 6, I have dupes of 1, 2, 4, 5, 7, and 8! 
-- A6
Bermag
Mon Nov 29, 2004 7:53 am
#2
Not on Bloodfin ao I can't help you.
I had RE hundreds of parts w/o any firespray schems. Then I had a bag with 50 items (all Kuat I bought when I though only Kuat coul give you the disks). From that bag I got 2 disks both part 6.
ArianSix
Mon Nov 29, 2004 7:55 am
#3
Wow you're lucky!
Yeah, of all my RE's, I've noticed that Kuat items seemed to have dropped about 50% of my discs... maybe even a little more.
-- A6
Arg0nus
Mon Nov 29, 2004 7:57 am
#4
I've RE'd close to 500 parts...and gotten no Firespray parts. 
Most of them were Kuat.
Niacia
Mon Nov 29, 2004 8:11 am
#5
Let us try some statistics.
Assumption: All disks drop with equal probability.
In this case, we get 8^21 possible outcomes for 21 disks, each outcome is equally likely.
Now, how many cases are there, where we do not get a full set?
One of 8 disks must be missing. This means, for each try we have to choose one of 7.
This gives us a total of 8*7^21 solutions. 8 for the decission, which disk is missing, and 7^21 possibilities for the complete series.
Now, we get a probability be dividing one trough the other.
p=(8*7^21)/(8^21)
This computes to 0.484461, or 48%. So your observation is not really unlikely.
Now let us calculate how many disks you need to find to be reasonable sure you get all disk.
At 30 disks there is still a chance of 14.5% you need to keep looking.
At 40 disks this drops to 3.8%
At 50 disks it is still at 1%. So some shipwrights are going to experience this.
60 disks: 0.2652%
70 disks: 0.07% Here I would say, this is very unlikely.
Regards
Niacia
Assumption: All disks drop with equal probability.
In this case, we get 8^21 possible outcomes for 21 disks, each outcome is equally likely.
Now, how many cases are there, where we do not get a full set?
One of 8 disks must be missing. This means, for each try we have to choose one of 7.
This gives us a total of 8*7^21 solutions. 8 for the decission, which disk is missing, and 7^21 possibilities for the complete series.
Now, we get a probability be dividing one trough the other.
p=(8*7^21)/(8^21)
This computes to 0.484461, or 48%. So your observation is not really unlikely.
Now let us calculate how many disks you need to find to be reasonable sure you get all disk.
At 30 disks there is still a chance of 14.5% you need to keep looking.
At 40 disks this drops to 3.8%
At 50 disks it is still at 1%. So some shipwrights are going to experience this.
60 disks: 0.2652%
70 disks: 0.07% Here I would say, this is very unlikely.
Regards
Niacia
ArianSix
Mon Nov 29, 2004 8:16 am
#6
Wow, nice math! So basically, if I get to 30 discs and still don't have a disc 6, I'm one unlucky nerfherder!
-- A6
Message Edited by ArianSix on 11-29-2004 07:16 AM
ArianSix
Mon Nov 29, 2004 8:18 am
#7
Arg0nus wrote:
I've RE'd close to 500 parts...and gotten no Firespray parts.
Most of them were Kuat.
While statistics are statistics, I like to wait until I have 300-400 items sitting around. Then I go through them in one large RE session.
I generally get 2-3 discs per session.
Hope this helps,
-- A6
Message Edited by ArianSix on 11-29-2004 07:18 AM
Brilyn
Mon Nov 29, 2004 8:19 am
#8
The law of averages vs. the law of probability.
Ultimately, you could get to 100 disks and still not get the one you want. Because the % chance of getting the one you want out of *each* RE remains constant.
Just keep plugging away, and talk to other SWs.
BTW, I'm wishing you were on Starsider. I have 2 excess 6s, and need 4 and 5. 
ArianSix
Mon Nov 29, 2004 8:22 am
#9
Brilyn wrote:
BTW, I'm wishing you were on Starsider. I have 2 excess 6s, and need 4 and 5.
Man, I'm wishing I was on Starsider too! I have about 4-5 each of discs 4 and 5. Would have had 6-7 5's but I traded 2 of them for 2 other discs that I already had just to even the stacks out a bit.
-- A6
Niacia
Mon Nov 29, 2004 8:52 am
#10
ArianSix wrote:Wow, nice math! So basically, if I get to 30 discs and still don't have a disc 6, I'm one unlucky nerfherder!-- A6Message Edited by ArianSix on 11-29-2004 07:16 AM
Actually, --
I hate to be the bringer of bad news, but for you the situation is worse.
For each additional disk, there is a 7/8 chance, that it is not the one you are looking for. You have 9 tries left to reach 30.
This means, the chance, that you will not get the disk during these 9 tries is:
p=(7/8)^9 =0.300658 or slightly higher then 30%....
The reason for this is, that you allready had bad luck. Those tries you used up, do not matter any more for you.
Of course the best bet is to find somebody to trade.
Regards
Niacia
ArianSix
Mon Nov 29, 2004 11:18 am
#11
Niacia wrote:
Actually, --
I hate to be the bringer of bad news, but for you the situation is worse.
For each additional disk, there is a 7/8 chance, that it is not the one you are looking for. You have 9 tries left to reach 30.
This means, the chance, that you will not get the disk during these 9 tries is:
p=(7/8)^9 =0.300658 or slightly higher then 30%....
The reason for this is, that you allready had bad luck. Those tries you used up, do not matter any more for you.
Of course the best bet is to find somebody to trade.
Regards
Niacia
Nooo... stupid bad luck. Alright, I'm going for 40 then... that's 19 more tries!
Ofcourse if anyone here on Bloodfin would like to trade some discs to help me break this bad luck streak that would be appreciated as well!
-- A6
DeathMvp2
Mon Nov 29, 2004 12:40 pm
#12
YOu are still doing beter then me. I have doen about 800 parts already (guild give them to me and I resell them for 1 cpu) and still only got 2 disk.
Cool1
Mon Nov 29, 2004 2:28 pm
#13
Arg i feel the pain of ignorance, well, towards understanding drop ratios anyways.
I got 7 disks in about 3 days from maybe 300 items, since then ive RE'd ATLEAST 1500 items and have gotten 0. Begining to wonder if they black listed me or something =/
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