Oz's Question of the day #214 (12/2/10) Maths !

[OZXJR]

A probability question for you.

Over the last 400 years,does one day of the week have the highest probability of being the 13th day of the month.Or do all the days have the same chance?

Hint:It has to be 400 years because of the leap years.

PM answers please.

 

[Fz6Sa]

Pm Sent :cheer:

 

[Senior]

PM'd my educated guess,
well actually I did some serious calculations,
but if I get it wrong it was definitely a guess

 

[Adirondack Jack]

I made no calculations and I'm sending a wild guess! I hate maths Fri.!!!!:ban:

 

[k1c]

Wrong answer on its way.

 

[Stevenator]

Wrong answer on its way.

What he said!

 

[SirIsaac]

PM sent...

 

[MaxRyan]

messaged..

 

[Coopdman]

I did it again! Accidentally posted my answer in the thread, just about had a heart attack once I realized it, and quickly deleted it to save face and the chance for others to play w/o my influence.

It's highly unlikely but not impossible that someone saw my answer. It's also very probable that due to my losing the original answer I might have reworked a slightly long-winded version of my once concise explanation. Sorry Mick, hope you enjoy reading Statistics FROM Dummies!

 

[teej21012]

PM sent.

 

[Live4Snow]

Sending PM......now.

 

[craig007]

guess on its way......

 

[Fz6Sa]

I did it again! Accidentally posted my answer in the thread, just about had a heart attack once I realized it, and quickly deleted it to save face and the chance for others to play w/o my influence.

It's highly unlikely but not impossible that someone saw my answer. It's also very probable that due to my losing the original answer I might have reworked a slightly long-winded version of my once concise explanation. Sorry Mick, hope you enjoy reading Statistics FROM Dummies!

Everybody subscribing to this thread, got your answer in their mailbox ......
Anyway, - I did not come up with the same answer as you, (It's the 13' of the month, not just the 13' of February ...)
so to everybody else: Don't automatic assume that Coop gave the right answer (not that I'm claiming that it is wrong), but do your own maths to solve this one

 

[OZXJR]

no more answers for todays question guys,will post the winners in the morning.

No worries Coop,all is fine ,and thanks Fz6sa :thumbup:

 

[Coopdman]

Everybody subscribing to this thread, got your answer in their mailbox ......
Anyway, - I did not come up with the same answer as you, (It's the 13' of the month, not just the 13' of February ...)
so to everybody else: Don't automatic assume that Coop gave the right answer (not that I'm claiming that it is wrong), but do your own maths to solve this one

How embarrassing! Sorry guys, I'll be more careful.

 

[OZXJR]

Answer.Friday has more chance over the given time to be the 13th day of the month.

Rep and casino cash winners:K1c,Max Ryan and Vinpub

Rep winners:SirIsaac and Teej21012

sorry for the delay guys

 

[Andz]

Can you give an explanation for those of us who have no clue?

 

[SirIsaac]

Can you give an explanation for those of us who have no clue?

Andz,
I'm not sure if I can give a succinct explanation. Basically arises out of the characterstics of the Gregorian calendar, which has a 400 year cycle, consisting of 303 years (common years) with 365 days and 97 years (leap years) with 366 days. There are 14 different kinds of years, common years starting on Monday, Tuesday, etc. and leap-years starting on Monday, Tuesday, etc. Each of these "types" of years will have a different distribution of 13ths of the month occuring on each day of the week. For example a common year beginning on a Monday will have 1 Monday, 3 Tuesdays, 1 Wednesday, 2 Thursdays, 2 Fridays, 2 Saturdays and 1 Sunday falling on the the 13th of the Month.

The "probability" difference for the 13th falling on the various weekdays is not that great. By my calculations, over the last 400 years there been the following numbers of 13ths of the month falling on the various weekdays:
Monday - 686
Tuesday - 684
Wednesday - 687
Thursday - 684
Friday - 689 (the winner!)
Saturday - 683
Sunday - 687