Math Baseball Mindfuck

[Unarmed Gunman]

Fractions are a huge part of baseball stats, but something doesn't make sense.

If a batter gets two hits in five at bats he is 2/5 = .400 batting average.

If he goes one for four in the next game he is now 3/9 = .333 batting average.

This is because when you add up his total hits (2+1) and divide by total at bats (5+4) you get 3/9. But when I try to add 2/5 + 1/4 (grade school style), I actually get 8/20 + 5/20 = 13/20 which would be a batting average of .650.

What the fuck am I doing wrong? Is this is a major math fail on my part or have I possibly discovered the secrets of time travel, division by zero and the answer to life the universe and everything in it? INB4 42.

 

[gimmedat]

You're not calculating it right. If he went 8/20 and then 5/20, that would be 40 at-bats.

13/40 = .325

 

[emp]

Yes, you are doing it wrong.

To get a batting (or any) average, you need to divide the total.

With your reasoning, if I would hit 3 balls out of 6 one game (3/6 or 1/2 = .5) and 2 of 4 the next game (2/4 or 1/2 = .5) I would have a batting average of 100 percent or
1/2 + 1/2 = 2/2 = 1

Whereas really, you need to take the total number of tries (6+4 = 10) and succesful hits (5) to get to the real number (5/10 or 1/2 or .5)

::emp::

 

[Deliguy]

to find the average of multiple percentages you don't add them together. You add then divide by the number of items.

 

[070707]

You're not calculating it right. If he went 8/20 and then 5/20, that would be 40 at-bats.

13/40 = .325

Beat me to it.

Basic Fail on the OP's part.

 

[Unarmed Gunman]

I figured it was something simple but after several beers last night during the game it had me and several friends fucked up. Guess I need smarter friends.

 

[MadMaxNine]

that's nothing bro, at your next get together if you really want to blow your minds try this one:

 

[juntao65]

You just multiply it by the denominator.

 

[Unarmed Gunman]

that's nothing bro, at your next get together if you really want to blow your minds try this one:

How does it work though?

 

[barman]

jesus fucking christ, America's public school system.

 

[barman]

How To Find The Least Common Denominator (LCD)

 

[MadMaxNine]

How does it work though?

Exactly...

 

[Unarmed Gunman]

How To Find The Least Common Denominator (LCD)

lulz - it's got nothing to do with LCD's barman. The issue was why 1/4 + 2/5 = 13/20 in math, but 3/9 in baseball. It has nothing to do with LCD - Eli was the only one that got the damn thing right.

 

[vince_c]

It's a pondered average, not an addition.

 

[barman]

lulz - it's got nothing to do with LCD's barman. The issue was why 1/4 + 2/5 = 13/20 in math, but 3/9 in baseball. It has nothing to do with LCD - Eli was the only one that got the damn thing right.

oh haha. +1 eli

 

[vince_c]

oh haha. +1 eli

If by Eli you mean deliguy, then he didn't get it right either unless the batter has the same number of tries every night.

It's a weighted average.

 

[WebairGerard]

baseball stats and batting averages helped save my ass back in the day when learning fractions in grade school!

 

[Moxie]

1/4 + 2/5 = 13/20 in math, but

1 quarter + 4 dimes = 65 cents (.65 of 1 dollar)

1 dollar is always 1 dollar. 1 at bat is also always 1 at bat, but the total amount of at bats is always changing, and this is what the average is in comparison to.

65 cents is always 65 cents, but it would be .325 of 2 dollars, .163 of 3 dollars...

 

[DanGlobalizer]

2/5 + 1/4 only equals 13/20 if you're a Scott Boras client.

 

[070707]

2/5 + 1/4 only equals 13/20 if you're a Scott Boras client.

:bowdown: