Chess reduces the chance of getting Alzheimers by 60 to 75 Percent

Where does the figure that chess reduces the chance of getting Alzheimer’s by 60-75% come from?

By Coach Patrick

It comes from the article written by the Associated Press (below in it’s entirety) that says that, “Adults with hobbies that exercise their brains — such as reading, jigsaw puzzles or chess — are 2.50 times less likely to have Alzheimer's disease, while leisure limited to TV watching may increase the risk, a study says.”

I looked at the figure given and it made no sense to me. “2.50 time less likely?” What percentage would that be? Not being a mathematician I searched online for help and found a “Mr. Math” who helped people with math problems and he confirmed my suspicion that it meant “60-75%” and he gave me the math to show it. (E-mail below) If you have any other information to verify or disprove this, please let me know.

Sincerely
Patrick Ellis
(Coach Patrick)

THE ARTICLE

Robert P. Friedland, MD

About the researcher- Professor, Robert P. Friedland, MD

http://www.netwellness.org/experts/biosketch.cfm?personid=413  

This article says that chess may reduce your chances of getting Alzheimer's by 75 percent:

http://www.healthywomen.org/columns/drpeekescolumn/dbcolumn/takeawalkpreventalzheimersdisease  

_____________________________________________________

THE EMAIL to SHOW CALCULATIONS

As Patrick wrote to Dr. Math
On 08/28/2007 at 00:37:25 (Eastern Time),

[Question]
If someone says "Research shows that people who play chess are 2.50 times less likely to get Alzheimer's disease than those who just watch TV.”

How can that be expressed in a percentage? I think the answer is that chess players are "60-75 percent less likely" to get Alzheimer's than those who just watch TV, but I'm not sure why. Am I correct? Can you show the math involved?

Thanks! Coach Patrick

[Answer]

Dear Patrick,

I think we have to be careful here; the phrase is something of an diom in English. If I took the phrase "2.5 times less likely" piece by piece, I'd say that 2.5 is the same as 250%, so it should mean the same as "250% less likely." The way we would calculate this is to take 250% of (or 2.5 times) the base number (the likelihood of getting Alzheimer's if you "just watch TV") and subtract this from the base number. However, if you do that, you get a negative likelihood, which makes no sense!

What you tried instead, if I follow your thoughts correctly, is to take "2.5 times less likely" to mean "1/2.5 times as likely." I think this is correct; it's what people mean by the expression.

Here is the logic, as far as I can see it: when they say "2.5 times less likely", they mean "less likely by a factor of 2.5". If you want to REDUCE a number in a multiplicative fashion, you need to DIVIDE by the factor rather than multiply. (Since the given factor is greater than 1, multiplying by it would increase the number rather than reducing it.) Thus the intent is to divide by 2.5, or equivalently, to multiply by the reciprocal of 2.5. Thus you express 1/2.5 as a percentage:

1 x
--- = --- ==> x = 100/2.5 = 40
2.5 100
I would suggest stopping here and saying that chess players are "40% as likely" to get Alzheimer's. But you want, I suppose, to get it back into the format of "... less likely", even though the meaning of the word "less" is significantly different in the new context. (It means to subtract, not to divide.) Given that this is what you want to do, you are correct that "40% as likely" is equivalent to "60 to 75% less likely."

Does this make sense?

TrackBack URI for this entry

Comments (19)

Subscribe to this comment's feed

ksharp said:

	After you have selected your character, you will appear in the Randol 1st level personal dungeon. You will fight the hordes of skeletons and monsters here. You first appear in a big room and as you approach the big doors they slowly open.silkroad.comsilcroad.comOnce you have gotten the first two smelts, then drag one smelt over your weapon.
	report abuse vote down vote up

March 11, 2010
Votes: +0

ksharp said:

	From the view of an outsider, World of Warcraft is just another Fantasy Game.WoW GoldBut Warcraft is much more than that. It is (to Players) a Real World.wow cd key
	report abuse vote down vote up

March 11, 2010
Votes: +0

ed hardy said:

The buy ed hardy are excellent products suitable for year-round wear. Many people all know Ugg boots uk? and know they are very popular. But less people know that the Australian brand found international recognition in the 1970s when an Australian surfer named Brian Smith took several pairs of Egg ed hardy for sale to the United States – soon the boots were a fashionable choice with the California surfer set, and these days are even seen in fashion shows of the worlds finest designers.

report abuse vote down vote up

February 24, 2010 | url
Votes: +0

bf29CATHERIN said:

	I do not opine that each student in whole world has a pa*sion of academic essay writing! Nevertheless, students that don't like writing have to use a support of professional custom cla*sification essays service and be satisfied with a success.
	report abuse vote down vote up

February 19, 2010 | url
Votes: +0

air jordan said:

	Dentist: I'm sorry, madam, but I'll have to charge you twenty-five dollars for pulling your son's tooth. Mother: Twenty-five dollars! But I thought nike air max you only charged five dollars for an extraction. Dentist: I usually do. But your son yelled so loud, he scared four other patients out of the office. nike air Max 180
	report abuse vote down vote up

February 18, 2010 | url
Votes: +0

ugg boots said:

	Wow, thanks for the insightful post.ugg boots I look forward to reading more from you.
	report abuse vote down vote up

February 05, 2010 | url
Votes: +0

ugg boots said:

	Wow, thanks for the insightful post. I look forward to reading more from you.http://www.cheapshoeshop.com/Nike-Air-Jordan-Shoes/Nike-Air-Jordan-19.html
	report abuse vote down vote up

February 05, 2010 | url
Votes: +0

uggbootshome said:

) Post-disaster restoration and reconstruction as a whole smoothly. As of the end of October 2009, tracking the audit of 72 key projects have been started, 65 completed 11 months, respectively, accounting for the number of audits for 90% and 15%; audit survey 753 schools have started 718, has completed 480 ,ugg boots respectively, accounting for the number of investigations, 95% and 64%. Audit survey of 22 counties in the planning of rural residential housing Maintenance and Reinforcement of 797.9 thousand, have all been completed; planning and redevelopment of 680,000, has started 666.6 thousand, have been completed 602.5 thousand, accounting for 98% of the planning tasks and 89%. The 22 counties of urban residential housing maintenance planning reinforcement 267.3 thousand, have all been started, has already been completed 212.9 thousand, accounting for 80% of the planning task; planning and redevelopment of 105.8 thousand, has started 61600, 25800 have been completed, respectively, accounted for 58% of the planning tasks and 24%.

report abuse vote down vote up

January 27, 2010 | url
Votes: +0

replica handbags said:

	genayiv0122 Replica Handbags Louis Vuitton Handbags
	report abuse vote down vote up

January 22, 2010 | url
Votes: +0

ugg store said:

	Good sharing! I don’t know whethercheap uggyou can read this message, but I think I should ugg bootstell you something about my attitude for you! I am so grateful for your sharing.
	report abuse vote down vote up

January 19, 2010 | url
Votes: +0

uggs said:

People who are always complaining about having to pay taxes are a bunch of sniveling deadbeats. What would you do with the extra money anyway? Spend it on crap most likely. You are being forced to discount ugg boots do something good in your lives for a change. The CBC, I grant you has a liberal bias, but then most Canadians are liberal, so it reflects their values. It can't be blamed for not pandering to right-wing hyenas; the broadcaster would not be able to plunge to the depths required to represent discount ugg bootsthe squalid opinions of such people.

report abuse vote down vote up

January 03, 2010 | url
Votes: +0

uggs said:

	http://www.japantouring.com/in...&Itemid=82
	report abuse vote down vote up

January 03, 2010 | url
Votes: +0

cheap ugg said:

People who are always complaining about having to pay taxes are a bunch of sniveling deadbeats. What would you do with the extra money anyway? Spend it on crap most likely. You are being forced to discount ugg boots do something good in your lives for a change. The CBC, I grant you has a liberal bias, but then most Canadians are liberal, so it reflects their values. It can't be blamed for not pandering to right-wing hyenas; the broadcaster would not be able to plunge to the depths required to represent discount ugg bootsthe squalid opinions of such people.

report abuse vote down vote up

December 31, 2009 | url
Votes: +0

ugg for sale said:

	Woods December 2 on their official website issued a statement admitting to his wife being unfaithful.ugg for sale The matter is far from over, saying it is Tiger Woods, lover of women, but to take out one after another, including bar girls, underwear model, television anchor woman, waitress,ugg sale etc., so far, the U.S. media exposure of the "tiger lovers" At least nine people.
	report abuse vote down vote up

December 31, 2009 | url
Votes: +0

sale uggs said:

	There is the most popular ugg boots in here ,sale uggs,ugg australia,ugg outlet,buy cheap ugg-70% OFF!Buy ugg on sale-discount ugg!!!
	report abuse vote down vote up

December 29, 2009 | url
Votes: +0

Ugg Boots said:

	Choose to wear a pair of boots is a very important thing, everyone familiar Cla*sic Ugg Boots is a warm autumn and winter boots, the more emphasis on style, the winter to a pair of legs can guarantee a comfortable and warm, 09 new autumn and winter uggs outlet snow is even more style than in the past more easily with snow boots.
	report abuse vote down vote up

December 29, 2009 | url
Votes: +0

uggs outlet said:

The Brazilian has been linked with a move to Barcelona in the January transfer window and has admitted that he will seek talks with Mancini to determine the new manager's plans for the club. City officially unveiled their new boss on Monday, with Mark Hughes sacked following Saturday's 4-3 victory over Sunderland.running shoes Mancini has placed Champions League qualification at the top of his ugg boots for sale ambitions for the season. He is also keen to build bridges with some of City's biggest names, with a number of first-team players expressing their disappointment at Hughes' departure.

report abuse vote down vote up

December 28, 2009 | url
Votes: +0

ugg boots on sale said:

I've often postulated that many boxers are on HGH. To my knowledge, running shoes not even a single blood test can detect HGH, but a series of blood tests administered over many weeks to detect the fluctuations causes by high doses of the stuff. Some folks have pituitary issues that can cause false positives. I spoke with a neurologist in depth on this subject, and he postulates that anywhere from 1 in 10 to 1 in 4 people have some kind of undetected tumor on their pituitary gland. Since that glad is the master control for all your glandsugg outlet, a person can have some really weird hormonal balances, not just hgh, but ANY hormone. So it's all a sticky wicket in that HGH testing isn't a test to detect cheaters that same way polygraphs don't detect lies.

report abuse vote down vote up

December 26, 2009 | url
Votes: +0

Joe Brown said:

"Times" is an expression for counting instances, which is the basis for both multiplication and division. But thinking of it directly as multiplication or (worse) division leads to all manner of errors. Idiomatic use of "times greater" to mean "times the size" causes (if not constitutes--and only not because of its ubiquity) hyperbole. It is not possible to universally consider "times less" as indicating division; evaluate "0.8 times less." Then evaluate "5 times less." In one instance you multiply, in the other you divide. In fall 2009, Ed Schultz began his first show on MSNBC by saying that health insurance premiums were "up 200%." He clearly depended on vernacular use of "2 times more," because (fortunately for careful viewers) he also included the before-and-after numbers. They supported a rounded number of only "up 100%," or a doubling. A perfect example of the deleterious effect of this idiom appear at http://theautochannel.com/news...14219.html Eradication of the locution would be a monumental task, but some try: http://grammarphobia.com/blog/...chive.html I would like to see the FTC ban its use in advertising ("Verizon has five times more 3G coverage...") as a start.

report abuse vote down vote up

November 29, 2009
Votes: +0

Name

Email

Website

Title

Comment

smaller | bigger

Subscribe via email (Registered users only)

I have read and agree to the Terms of Usage.

Write the displayed characters

Add Comment