Interesting Statistics

[cmarques]

So I passed my Skills test today :Rockon:. After I passed I started thinking...

I took both my car and motorcycle road tests on Friday the 13ths and passed first try on both. I asked myself, what are the odds?

Well a year can have at most 3 Friday the 13ths so randomly picking a road test on a friday the 13th is at best 3/365. Since I was scheduled twice on different Friday the 13ths then that makes my odds 9/133225.
Since I passed both times first try then lets say that the pass rate (first try in NY) is at best 50% then my odds for all this happening to someone else is.... ~0.00002 or about 1 out of 50000

 

[bonesfz1]

Intersting research. Got some time on your hands I see..j/k..

 

[lindy]

You are indeed special!

But could you not do the same time thinking and calculations of driving through an intersection at a specific instant....
....or anything else , for that matter?

But the Friday the thirteenth stuff is kinda cool....

 

[Crazyjoe]

So I passed my Skills test today :Rockon:. After I passed I started thinking...

I took both my car and motorcycle road tests on Friday the 13ths and passed first try on both. I asked myself, what are the odds?

Well a year can have at most 3 Friday the 13ths so randomly picking a road test on a friday the 13th is at best 3/365. Since I was scheduled twice on different Friday the 13ths then that makes my odds 9/133225.
Since I passed both times first try then lets say that the pass rate (first try in NY) is at best 50% then my odds for all this happening to someone else is.... ~0.00002 or about 1 out of 50000

Your statistics are skewed since you know too much about math.

 

[Evitzee]

Did you have any input into scheduling them on a Friday or on the 13th of the month or were they truly random? Does the DMV test every weekday or only certain days? These facts will change the odds dramatically. Even if the dates were picked for you you skewed the results by asking for a date in a month that has a Friday the 13th in it. In your case it doesn't seem to be totally random, your odds are a lot lower than you calculate. I suspect the pass rate is greater than 50% in most places, especially for a car.

 

[cshrumfz1]

Did you have any input into scheduling them on a Friday or on the 13th of the month or were they truly random? Does the DMV test every weekday or only certain days? These facts will change the odds dramatically. Even if the dates were picked for you you skewed the results by asking for a date in a month that has a Friday the 13th in it. In your case it doesn't seem to be totally random, your odds are a lot lower than you calculate. I suspect the pass rate is greater than 50% in most places, especially for a car.

I'll bite...:hook2:

Adding to that, they certainly do not test on weekends...and there are 53 Saturdays this year, and 52 Sundays. There goes 105 of your 365, knocking you down to "only" 260 days. Holidays with the gov't are like bankers days, so they are likely shut for each and every conceivable American holiday (MLK, Pres. Day, Columbus, Christmas, Thanksgiving, etc.), so now we're down to 250-ish.
Do they test every single day that they are open? CO has riding tests done only on certain days...but I would think that NY has a little more people to try and get through the system...

just sayin'...oke:

 

[Recon Viper 1]

So I passed my Skills test today :Rockon:. After I passed I started thinking...

I took both my car and motorcycle road tests on Friday the 13ths and passed first try on both. I asked myself, what are the odds?

Well, that's not something that I am familiar with at all.

Texas is still a Free State and doesn't require me to demonstrate "skills" following any qualifications for certification except for Concealed Handgun Practical requals.

I can only guess that it is something devised by the leanings of the government of your State but I do give respect to the coincidence of the test dates.

Good work!

 

[Clyde]

Are you saying that Texas doesn't have a testing requirement for motorcycle (or car) licenses? I thought that they would accept MSF certification, or a road test in order to get your license.

 

[cmarques]

I'll bite...:hook2:

Adding to that, they certainly do not test on weekends...and there are 53 Saturdays this year, and 52 Sundays. There goes 105 of your 365, knocking you down to "only" 260 days. Holidays with the gov't are like bankers days, so they are likely shut for each and every conceivable American holiday (MLK, Pres. Day, Columbus, Christmas, Thanksgiving, etc.), so now we're down to 250-ish.
Do they test every single day that they are open? CO has riding tests done only on certain days...but I would think that NY has a little more people to try and get through the system...

just sayin'...oke:

So if we take only 250 days into account than that still doesn't change the order of magnitude of the original probability. We still have at best 3/250 change of getting a Friday the 13th and say the rate of success is 3/4 for passing your road test for both tests. That still leaves a probability of 0.000081 or 1 out of 12,000. Granted a much smaller number but still on the order of my original post and still these calculations were performed with the "at best" assumptions.

 

[Evitzee]

Well, that's not something that I am familiar with at all.

Texas is still a Free State and doesn't require me to demonstrate "skills" following any qualifications for certification except for Concealed Handgun Practical requals.

I can only guess that it is something devised by the leanings of the government of your State but I do give respect to the coincidence of the test dates.

Good work!

Hold on there, grasshopper, TX certainly requires a skill test to operate a motorcycle. If you have a MSF test certificate this will suffice, and in the past if you moved to TX and had a license from another state that had a m/c endorsment this would be honored (don't know if this is the case any longer). Here's the dope from TX Department of Public Safety, probably not much different from other states. And Texas may be 'free-er' than many states but we have plenty of stupid laws and regulations in the Lone Star State intended to extract money or restrict freedom.

TxDPS - Motorcycle License

 

[WABBMW]

cmarques:

I took a statistics course in college, and find the topic interesting, but I must quote a line from some movie such as "American Graqfetti":

Cmarques, "you are just mentally playing with yourself".

Hey, all in good fun. I am probably even more guilty of doing the same.

 

[cmarques]

cmarques:

I took a statistics course in college, and find the topic interesting, but I must quote a line from some movie such as "American Graqfetti":

Cmarques, "you are just mentally playing with yourself".

Hey, all in good fun. I am probably even more guilty of doing the same.

You're probably right but one thing that I know we all can agree on is that it is always fun when you play with yourself..

 

[packnrat]

Hold on there, grasshopper, TX certainly requires a skill test to operate a motorcycle. If you have a MSF test certificate this will suffice, and in the past if you moved to TX and had a license from another state that had a m/c endorsment this would be honored (don't know if this is the case any longer). Here's the dope from TX Department of Public Safety, probably not much different from other states. And Texas may be 'free-er' than many states but we have plenty of stupid laws and regulations in the Lone Star State intended to extract money or restrict freedom.

TxDPS - Motorcycle License

and be-aware the liberals of kliaournia are breading and spreading like a virus across our country. :sinister:

 

[Darth5oh]

If a year can have at most 3 Friday the 13ths, same is true for Friday the 11th, 12th, 14th, 15th, 16th and so on…

I graduated in statistics/probability. What you did was “back-door” into your odds AFTER the FACT, making your conclusion completely meaningless.

An example using your logic, would be to flip a coin 10 times in a row, record the result (let’s say 5 heads in a row, followed by 5 tails in a row) , and then be amazed because the odds of doing that randomly would be .5 (50%) to the 10th power (10- coin flips), or only a .09765625% chance.

Also, passing your tests had little to do with “odds.” It's directly related to your amount of preperation for the test. (Studying stacks the odds in your favor.)

All that said, congratulations on passing! Lol!

 

[cmarques]

If a year can have at most 3 Friday the 13ths, same is true for Friday the 11th, 12th, 14th, 15th, 16th and so on…

I graduated in statistics/probability. What you did was “back-door” into your odds AFTER the FACT, making your conclusion completely meaningless.

An example using your logic, would be to flip a coin 10 times in a row, record the result (let’s say 5 heads in a row, followed by 5 tails in a row) , and then be amazed because the odds of doing that randomly would be .5 (50%) to the 10th power (10- coin flips), or only a .09765625% chance.

Also, passing your tests had little to do with “odds.” It's directly related to your amount of preperation for the test. (Studying stacks the odds in your favor.)

All that said, congratulations on passing! Lol!

Thanks!

Now I didn't earn a degree in statistics so please forgive me for my silly calculations but the fact that i calculated AFTER it happened doesnt make it completely meaningless. Indeed your example shows how I came to my conclusion and 1/1024 odds are pretty low but still if something happened to you which you thought was highly unlikely wouldnt you like the chance to find out just how unlikely?

PS: The whole point about this post was to alleviate some of the stigma behind Friday the 13th and how unlucky of a day it is =)

 

[stretch]

So I passed my Skills test today :Rockon:. After I passed I started thinking...

I took both my car and motorcycle road tests on Friday the 13ths and passed first try on both. I asked myself, what are the odds?

Well a year can have at most 3 Friday the 13ths so randomly picking a road test on a friday the 13th is at best 3/365. Since I was scheduled twice on different Friday the 13ths then that makes my odds 9/133225.
Since I passed both times first try then lets say that the pass rate (first try in NY) is at best 50% then my odds for all this happening to someone else is.... ~0.00002 or about 1 out of 50000

my math comes out a bit differently.
there are at most 52 fridays in a givven year 3 of which may be a friday the 13th So since you went on a friday both times there was a one in 17ish chance of it being a friday the 13th. Now there were too possible outcomes pass/fail so the odds of passing your driving test on a friday the 13th if you go on a friday are X=2^17 that's 2 to the 17th power or about 1 in 131,072

 

[cmarques]

my math comes out a bit differently.
there are at most 52 fridays in a givven year 3 of which may be a friday the 13th So since you went on a friday both times there was a one in 17ish chance of it being a friday the 13th. Now there were too possible outcomes pass/fail so the odds of passing your driving test on a friday the 13th if you go on a friday are X=2^17 that's 2 to the 17th power or about 1 in 131,072

The assumption I made was my road test could be scheduled at any day of the week, not just Fridays. I guess the next question is, which days of the week DMV actually performs road tests?