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Friggatriskaidekaphobia

Friggatriskaidekaphobia

RE: Friggatriskaidekaphobia

I never notice it is Friday the 13th until someone else mentions it, then I get a little superstitious. I didnt know there was an actual "phobia" for it or a name for it. At least it is easy to pronounce. [wink]
Come to think of it, a dark colored squirrel did try to cross the road in front of me on the way to work this morning......

Learning - A never ending quest for knowledge usually attained by being thrown in a situation and told to fix it NOW.

RE: Friggatriskaidekaphobia

On my way to work I passed by a car fire on the highway. Someone was obviously having an unlucky day.

RE: Friggatriskaidekaphobia

Found a penny this morning. Gotta be good luck!

Aspiring to mediocrity since 1957

RE: Friggatriskaidekaphobia

Heads up or down?

Learning - A never ending quest for knowledge usually attained by being thrown in a situation and told to fix it NOW.

RE: Friggatriskaidekaphobia

I'm reposting an interesting tidbit I learned recently to this forum for those that might not have seen it in STC.

Statistically, the 13th day of the month falls more frequently on a Friday than any other day of the week. (the difference is insignificant but real)

Cool fact of the day.

**********************************************
What's most important is that you realise ... There is no spoon.

RE: Friggatriskaidekaphobia

Quote (DrB0b)

Heads up or down?
Hey, if I find a penny it's good luck regardless of which side is up or down. I'm a penny richer. winky smile

James P. Cottingham
I'm number 1,229!
I'm number 1,229!

RE: Friggatriskaidekaphobia

Quote (kwbMitel)

I'm reposting an interesting tidbit I learned recently to this forum for those that might not have seen it in STC.

Statistically, the 13th day of the month falls more frequently on a Friday than any other day of the week. (the difference is insignificant but real)

Cool fact of the day.

I find that hard to believe. Given a long enough time span, I would think it would have a pretty even distribution across all days of the week.

Do you have a link to the thread where this was discussed?

RE: Friggatriskaidekaphobia

What about 6, 20, and 27 they will fall on a Friday every time the 13 falls on a Friday.

djj
The Lord is my shepherd (Psalm 23) - I need someone to lead me!

RE: Friggatriskaidekaphobia

Quote:

The distribution of the 13th day over the 4,800 months is as follows:
Day of the week
Number of occurrences
Sunday 687
Monday 685
Tuesday 685
Wednesday 687
Thursday 684
Friday 688
Saturday 684
Link here: http://en.wikipedia.org/wiki/Friday_the_13th

RE: Friggatriskaidekaphobia

OK, here's the scoop on the Frequency of the 13th for each day of the week.

For this year, 2012, the 13th of the month has this frequency...

CODE

13th frequency from January 2012 through December 2012

Sundays    = 1
Mondays    = 2
Tuesdays   = 2
Wednesdays = 1
Thursdays  = 2
Friday     = 3
Saturdays  = 1 

That is more Friday 13ths than any other day 13ths. Looking at the years 2000 through the end of 2012...

CODE

13th frequency from January 2000 through December 2012

Sundays    = 23
Mondays    = 21
Tuesdays   = 24
Wednesdays = 21
Thursdays  = 24
Friday     = 22
Saturdays  = 21 

...it looks like Tuesdays, Thursdays, and Sundays have the edge over Friday.

Checking it for January 1900 through the end of the year 2012, it looks like Tuesday has more 13ths than any other day, by a whopping 1. But it's still a very close even distribution across all days of the week.

CODE

13th frequency from January 1900 through December 2012

Sundays    = 193
Mondays    = 193
Tuesdays   = 195
Wednesdays = 193
Thursdays  = 194
Friday     = 194
Saturdays  = 194 

Here's the code if anyone wants to check it.

CODE --> 13.ksh

#!/bin/ksh

MIN_YEAR=1900
MAX_YEAR=2012

YEAR=${MIN_YEAR}

SUNDAY=0
MONDAY=0
TUESDAY=0
WEDNESDAY=0
THURSDAY=0
FRIDAY=0
SATURDAY=0

while (( YEAR <= MAX_YEAR ))
do
        for MONTH in 1 2 3 4 5 6 7 8 9 10 11 12
        do
          cal ${MONTH} ${YEAR} | grep 13 | tail -1 | read SUN MON TUE WED THU FRI SAT

          (( SUN == 13 )) && (( SUNDAY += 1 ))
          (( MON == 13 )) && (( MONDAY += 1 ))
          (( TUE == 13 )) && (( TUESDAY += 1 ))
          (( WED == 13 )) && (( WEDNESDAY += 1 ))
          (( THU == 13 )) && (( THURSDAY += 1 ))
          (( FRI == 13 )) && (( FRIDAY += 1 ))
          (( SAT == 13 )) && (( SATURDAY += 1 ))
        done

        (( YEAR += 1 ))
done

print
print "13th frequency from January ${MIN_YEAR} through December ${MAX_YEAR}"
print
print "Sundays    = ${SUNDAY}"
print "Mondays    = ${MONDAY}"
print "Tuesdays   = ${TUESDAY}"
print "Wednesdays = ${WEDNESDAY}"
print "Thursdays  = ${THURSDAY}"
print "Friday     = ${FRIDAY}"
print "Saturdays  = ${SATURDAY}"
print

# EOF 

RE: Friggatriskaidekaphobia

Perhaps Im missing a variable here, but are you taking into account, Feb = 28 days and every other month either 30 or 31? It appears to me you generalized the months to have the same number of days, but it is Friday and I may have my, "let's go home and take a nap" hat on...

Learning - A never ending quest for knowledge usually attained by being thrown in a situation and told to fix it NOW.

RE: Friggatriskaidekaphobia

Sambones - you need to use a 400 year cycle minimum or multiple thereof to allow for the centuries that do not have leap years.

**********************************************
What's most important is that you realise ... There is no spoon.

RE: Friggatriskaidekaphobia

4800 months is 400 years. Here's what my scripts gives for 400 years...

CODE

13th frequency from January 1613 through December 2012

Sundays    = 684
Mondays    = 685
Tuesdays   = 686
Wednesdays = 687
Thursdays  = 685
Friday     = 688
Saturdays  = 684 

Friday is ahead by only 1. That's a 0.1% advantage. I'm not sure if that's significant or not.

My code choked on September 1752. There is no 13th in that month (according to the "cal" program").

CODE

$ cal 9 1752
   September 1752
 S  M Tu  W Th  F  S
       1  2 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30 

Running the scripts for 800 years, I get this...

CODE

13th frequency from January 1213 through December 2012

Sundays    = 1370
Mondays    = 1371
Tuesdays   = 1370
Wednesdays = 1374
Thursdays  = 1370
Friday     = 1375
Saturdays  = 1369 

Friday is still ahead, but again, only by 1. That's only a 0.07% advantage.

RE: Friggatriskaidekaphobia

@ Sambones - reread my original post and you will find the following:

(the difference is insignificant but real)

Some might even argue that .1% is not insignificant depending on your point of view

**********************************************
What's most important is that you realise ... There is no spoon.

RE: Friggatriskaidekaphobia

DrB0b, the number of days in the month is accounted for. I'm using the "cal" utility to get the calendar for each month, then just pulling out the week with a 13 in it. I look to see what day that 13 landed on, then add one to that counter. Do it doesn't matter how many days are in the month. I'm trusting "cal" to give me a correct month.

Here's the "cal" output for this month...

CODE

$ cal 7 2012
   July 2012
 S  M Tu  W Th  F  S
 1  2  3  4  5  6  7
 8  9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 

I've bolded the line that the script pulls out to test for which day it's on.

Just for grins, I ran it starting in the year 1. I realize our calendar didn't exist in its current form then, but here it is anyway.

CODE

13th frequency from January 1 through December 2012

Sundays    = 3449
Mondays    = 3448
Tuesdays   = 3449
Wednesdays = 3451
Thursdays  = 3448
Friday     = 3453
Saturdays  = 3445 

Friday still in the lead.

RE: Friggatriskaidekaphobia

Figured as much, just clarifying. Thanks for the follow up.

Learning - A never ending quest for knowledge usually attained by being thrown in a situation and told to fix it NOW.

RE: Friggatriskaidekaphobia

>My code choked on September 1752. There is no 13th in that month (according to the "cal" program").

Correct. That was when we changed from The Julian Calendar to the Gregorian Calendar. Cal has the correct dates for September.

RE: Friggatriskaidekaphobia

Cool factoid #2 - Sept 13, 1752 never happened.

**********************************************
What's most important is that you realise ... There is no spoon.

RE: Friggatriskaidekaphobia

Quote:

Cool factoid #2 - Sept 13, 1752 never happened.
Except of course for those countries (Russia for example) that did not switch until much later. For them, it was dates as usual and September 13 1752 did happen. Your "cool factoid" is hot and steamingly full of western/Anglo-centricities.

Quote:

Correct. That was when we changed from The Julian Calendar to the Gregorian Calendar. Cal has the correct dates for September.
As long as "we" (and Cal) ignore other parts of the world.

Gerry

RE: Friggatriskaidekaphobia

I guess I should say that I am not trying to be catty, I just think it is better to be explicit. There may not have been a September 13 1752 in British history, but there WAS a September 13 1752, so stating there was not is incorrect.

Gerry

RE: Friggatriskaidekaphobia

While we're on the subject of dates and policital correctness smile I noticed an article in Wikipedia recently talking about 36,000 years BP (Before Present). Sacrificing a fixed reference point (BC/AD), no matter how theologically debatable, in favour of a moving target seems ludicrous to me! I vote for Unix time since the epoch... winky smile

Annihilannic
tgmlify - code syntax highlighting for your tek-tips posts

RE: Friggatriskaidekaphobia

(OP)
Please, let's not let this thread turn into something that is not appropriate for MAI.

--------------
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RE: Friggatriskaidekaphobia

On 7/13/12:

* My work computer crashed.

* A neighbor's ladder fell with him on it. He's OK.

* The mail carrier's delivery truck had a failure in from of my mailbox.

* I saw a black cat at 11:59PM. It walked right in front of me as I sat outside enjoying the summer weather. I know it was 11:59PM as I glanced at my watch.

I am not a superstitious person but it was an interesting day...

I keep trying to do something about my procrastination but I keep putting it off until tomorrow.

RE: Friggatriskaidekaphobia

Although it did not happen on a Friday, let us for a moment remember the "most successful failure in history" and its mind-boggling accumulation of thirteens:

- The 13th Apollo moon mission was launched at 13:13 hours Central time from pad 39.
- The first names of the three astronauts (James, Fred and John) had a total of 13 letters.
- On April 13, an oxygen tank exploded.
- The resulting pressure inside the compartment popped the bolts attaching the 13-foot Sector 4 outer aluminum skin panel.
- Mechanical shock forced the oxygen valves closed on the number 1 and number 3 fuel cells.
- The leaking relief valve caused the oxygen tank contents to leak out into space over the next 130 minutes.

According to unconfirmed rumours the crew had managed to connect the cube-shaped air filter canisters to the lifeboat's cylindrical canister-sockets using the freshly skinned hide of a black cat that had hidden under the entry ladder [citation needed].

Text combined from information gathered at Wikipedia and NPR.

“Knowledge is power. Information is liberating. Education is the premise of progress, in every society, in every family.” (Kofi Annan)
Oppose SOPA, PIPA, ACTA; measures to curb freedom of information under whatever name whatsoever.

RE: Friggatriskaidekaphobia

This is another 13 stat I bring out sometimes:

Argument for 132 being the most perfect square

132 = 169
132 = 122 + 52
1+6+9 = 42
1, 16, and 9 are all squares
312 = 961 (this one I find the most interesting)

There are more but they get a little too sketchy in connections. e.g. 32*42+52 is just a rehash of 122+52

**********************************************
What's most important is that you realise ... There is no spoon.

RE: Friggatriskaidekaphobia

Quote (MakeItSo)

According to unconfirmed rumours the crew had managed to connect the cube-shaped air filter canisters to the lifeboat's cylindrical canister-sockets using the freshly skinned hide of a black cat that had hidden under the entry ladder [citation needed].
rofl

James P. Cottingham
I'm number 1,229!
I'm number 1,229!

RE: Friggatriskaidekaphobia

Just to dispel the notion, I went to the dentist and I had no bad news!

Jim C.

RE: Friggatriskaidekaphobia

Found this thread and thought I would share.

Friday 13th July - The day my tire had a blow out on the motorway.


:(

"I'm worried and confused. So the first rule in the book is to spread it around."

RE: Friggatriskaidekaphobia

Did you manage to get off the road safely?

Annihilannic
tgmlify - code syntax highlighting for your tek-tips posts

RE: Friggatriskaidekaphobia

Luckily, was just exiting the motorway and the front left tire blew, pulling me in the direction of (and up the slip road) got to the top of the road and stopped in a safe place.

I was only driving for 1 month at this point; not the best experience for a new driver! There was a hole the size of a ping pong ball in the tire.

"I'm worried and confused. So the first rule in the book is to spread it around."

RE: Friggatriskaidekaphobia

Well, that's what you get for driving on Friday the 13th! What were you thinking?!?

bigsmile


RE: Friggatriskaidekaphobia

I've always had the fear of pronouncing Friggatriskaidekaphobia without it sounding like a nasty word.

sam

RE: Friggatriskaidekaphobia

SamBonmes,

the greogorian calender repats every 400 years, every inexactness betwen it and the astrological position of earth is accounted for by leap seconds, but they don't affect the statistics for Friday, the 13ths. That is your data on the 800 year interval should have double the counts of your 400 year run, but your 400 years run is incorrect.

For any span of 400 years you should get the following counts:

CODE

Sun: 687
Mon: 685
Tue: 685
Wed: 687
Thu: 684
Fri: 688
Sat: 684 

I counted this for different periods of each 400 years (1600-1999, 1700-2099, 1613-2012) and always got the same statistic.

This 688 does not differ much from your finding, it is the insignificant higher number of fridays at the 13th than other 13ths. But the point is, the distribution doesn't get even over higher periods, because the calendar repeats, so this distribution is what also repeats and is multiplied, if you take into account 800,1200, etc. years.

Bye, Olaf.

RE: Friggatriskaidekaphobia

>astrological position
That of course should be the astronomical position. :D

Bye, Olaf.

RE: Friggatriskaidekaphobia

I attribute any inaccuracies to the "cal" utility from which I pulled my data. I was just collating what it reported.



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