• Welcome to the Speedsolving.com, home of the web's largest puzzle community!
    You are currently viewing our forum as a guest which gives you limited access to join discussions and access our other features.

    Registration is fast, simple and absolutely free so please, join our community of 35,000+ people from around the world today!

    If you are already a member, simply login to hide this message and begin participating in the community!

OLL and PLL skip chances

Lt-UnReaL

Member
Joined
Dec 6, 2006
Messages
1,142
Location
Rochester, NY
WCA
2008CLAY01
Apparently the chances for an OLL skip is 1/216 solves. I've never gotten an OLL skip in any speedsolve in the passed 5 months, and I solve about 30 times a day.

This one also comes up 1/216. I've gotten this OLL about 4 times in the last 3 days, about 90 solves.

That's equivalent to 1/22.5 solves...Of course I was just lucky, but I have gotten this at least 10 times in the passed 5 months, and no OLL skips...

Now the chances for PLL skips are 1/72. I've gotten about 3-4 PLL skips in the passed 5 months, but at least 15-20 N perms(about 7-10 for each one). They also come up 1/72...

How can these numbers be right? How can people get OLL/PLL skips all the time and I never get them... :(
 

joey

Member
Joined
Apr 8, 2007
Messages
4,410
WCA
2007GOUL01
YouTube
cardologist
You do know that these probablities are not-mutual.
You could do 10,000 solves and get a LL skip everytime, it is unlikely but it could happen because one solve does not affect the probablities of the next solve.

The probability for an OLL skip on one solve is 1/216, you can't do 216 solves and expect an OLL skip. The probabilities come from the states of the cube, where 1 out of 216 states is an OLL skip.
 

Lofty

Member
Joined
Jun 4, 2007
Messages
1,585
Location
Gainesville, Florida
WCA
2008LOFT01
YouTube
Loftycuber
wow...
I never got OLL skips either excpet when I do VHF2L but then my chances are a little different.
I get 2 or 3 PLL skips a day but I don't time most of my solves since they are just to keep me entertained as I walk 15 minutes to class. But I solve a lot more cubes a day than you.
 

clincher

Member
Joined
Aug 21, 2007
Messages
146
The probability for an OLL skip on one solve is 1/216, you can't do 216 solves and expect an OLL skip.
Wrong! One OLL skip is *exactly* what you should expect.
I don't understand. What I use to understand is that 1/216 expressed the probabilities of an OLL skip but lets say the case 158 repeated a lot so I wouldn't have a OLL skip until the other 215 cases have been experienced.
 

DanHarris

Member
Joined
Oct 6, 2006
Messages
105
Location
Norwich, UK
yeah, Stefan is right. But I think Joey's point is that if you didn't have an OLL skip in solve 1, you shouldnt expect the chances for an OLL skip in solve 2 to be reduced. The probability is a constant 1/216

Dan
 

Ron

Member
Joined
Sep 9, 2006
Messages
337
Location
Amsterdam
WCA
2003BRUC01
You have more frequent OLL skips if you can (partially) control LL edge orientation during F2L.
There are some regular VHF2L cases that you can learn to orient LL during F2L.
 

Theromy

Member
Joined
Sep 3, 2007
Messages
93
I've had 3 or 4 OLL skips in the one and a half months I've been cubing with fridich, I've had about 5 PLL skips, they always happen when I'm not timing myself, just when I'm messing around.
 

Protest

Member
Joined
Aug 22, 2007
Messages
27
Location
not the US of A
yea in my last 5 solves, i hade 2 pll skips, and one oll skip, well i did one lol i think, cant remember, but quite odd. nice times for a noob tho:D
 

Lt-UnReaL

Member
Joined
Dec 6, 2006
Messages
1,142
Location
Rochester, NY
WCA
2008CLAY01
The probability for an OLL skip on one solve is 1/216, you can't do 216 solves and expect an OLL skip.
Wrong! One OLL skip is *exactly* what you should expect.
I suppose it was the way I worded it.

You should *expect* one OLL skip, but it does not mean you *will* get that one OLL skip.


Stefan: Correct?
Yeah, I knew this. I'm just saying the chances for a person to solve it like 1,500 times and only receive 1 OLL skip out of them all are pretty bad.

As the number of cubes you solve approaches infinity the ratio of OLL skips you get will approach 1/216
Ah, this makes more sense.
 

annon

Member
Joined
Nov 30, 2006
Messages
86
I'm pretty sure the odds of encountering either skip a single time can be represented by exponential decay functions. O(X) for OLL cases, P(X) for PLL cases, X for the number of solves.

O(X) = 1 - (215/216)^X
P(X) = 1 - (71/72)^X
 
H

hdskull

Guest
i get way more PLL skips than OLL skips, excepted for the controlled ones.
 
Top