Follow Slashdot stories on Twitter

 



Forgot your password?
typodupeerror
Books

Book Review: The Terrorists of Iraq 263

Posted by samzenpus
from the read-all-about-it dept.
benrothke writes: The infinite monkey theorem states that a monkey hitting random typewriter keys for an infinite amount of time will eventually be able to create the complete works of Shakespeare. Various scientists such as Nobel laureate Arno Penzias have shown how the theorem is mathematically impossible. Using that metaphor, if you took every member of United States Congress and House of Representatives and wrote their collected wisdom on Iraq, it's unlikely they could equal the astuteness of even a single chapter of author Malcolm W. Nance in The Terrorists of Iraq: Inside the Strategy and Tactics of the Iraq Insurgency 2003-2014. It's Nance's overwhelming real-world experiential knowledge of the subject, language, culture, tribal affiliations and more which make this the overwhelming definitive book on the subject. Read below for the rest of Ben's review.

Comment: Re:We're so screwed. (Score 1) 237

You're technically correct but they are only selectively dependent. If you don't die, the fact that you didn't die that year does not change the likelihood that you will die in the next year. This fact is sufficient for P(X and Y) = P(X) * P(Y) to hold for us because we are looking specifically at the probability that you DON'T die from terrorism over your lifetime. We make the dependency when you DO die irrelevant. That's why I took the path I did to answer the question "What are the chances you'll die from terrorism if you would otherwise live 75 years?"

To illustrate this, lets simplify things and take a look at a classic example: picking colored marbles from a jar. We are going to take a step back from the individual perspective and see what the probability is that a specific marble will get picked out of a larger population.

You have a jar with 3 marbles in it. 1 marble is yellow, {Y} (representing you) and 2 marbles are orange, {O1} and {O2} (representing other people). Every year, 1 marble is removed from the jar by a terrorist (representing death). And at the end of every year, 1 orange marble is added to the jar (representing someone else being born).

In year 1, there are 3 possible outcomes. 1 where the yellow marble is chosen. 2 where an orange marble is chosen.

Outcome 1: {Y}
Outcome 2: {O1}
Outcome 3: {O2}

At the end of year 1, orange marble {O3} is added. In year 2, there are 9 possible outcomes. We can apply the formula from my previous post to this. What does it say?

P(yellow will be picked over 2 years) = 1 - ((1 - (1/3))^2) = 1 - ((2/3)^2) = 1 - 4/9 = 5/9

So we would expect 5 of the outcomes to have yellow picked. Here's a table of the outcomes:

___Yr1__Yr2__
O 1 {Y}__ {O1}
U 2 {Y} __{O2}
T 3 {Y} __{O3}
C 4 {O1}_{Y}
O 5 {O1}_{O2}
M 6 {O1}_{O3}
E 7 {O2}_{Y}
# 8 {O2}_{O1}
_ 9 {O2}_{O3}

As represented by the math, there are 5 out of 9 outcomes in this table where yellow was picked. You can take this to 3 years and beyond. At 3 years, we would expect to see 8 in 27 outcomes where yellow was not picked. This makes sense if you look at the table above because outcomes 5, 6, 8, and 9 are the only ones that can generate a new outcome where yellow was not picked. In the new table, they generate 2 such outcomes each and 2 * 4 = 8.

Hopefully that clears things up a bit.

Comment: Re:We're so screwed. (Score 1) 237

Here's what's wrong: my value is a 0 to 1 probability. Yours is a 0-100%. So my overestimation is actually close to yours. That being said, let me explain why I'm not asking how many times you'll die from terrorism over 75 years.

The line was:

P(Terrorist DOESN'T kill you in your lifetime) = P(Terrorist DOESN'T kill you in a specific year) ^ 75

It works like this:

What is the probability that I will survive this year? 0.999999
In order to survive for 2 years, I have to survive this year and survive next year. In statistics, P(X and Y) = P(X) * P(Y).

So the probability that you'll live for two years is 0.99999^2. And to survive 75 years is 0.999999^75

Comment: Re:We're so screwed. (Score 2) 237

You can figure out the chance you'll die from terrorism with some statistical math if you choose an expected lifetime length and your chance to die from terrorism each year. The math is fairly simple if you assume that your chance of dying from terrorism is roughly constant over your lifetime. It's not perfect but it can give you an idea of the magnitude of the risk involved.

Let P(terrorist kills you in your lifetime) be the probability of a terrorist killing you in your lifetime. Then,

P(terrorist kills you in your lifetime) = 1 - P(terrorist doesn't kill you in your lifetime)

If we assume that the likelihood of dying in a terrorist attack is fairly constant over your lifetime then:

P(terrorist doesn't kill you in your lifetime) = P(terrorist doesn't kill you in a specific year) ^ N

Where N is the number of years you expect to live. Lets overestimate the number of people that die from the kinds of terrorists you see on the news in the United States in a year. I do not see headlines about 100 people dying a year from actual terrorists but still I am going to overestimate and say it's a 1 in a million chance. So around 300 people dead a year in the U.S.A.

P(terrorist doesn't kill you in a specific year) = 1 - P(terrorist kills you in a specific year) = 1 - 0.000001 = 0.999999

So the formula looks like this:

P(terrorist kills you in your lifetime) = 1 - ((1 - P(terrorist kills you in a specific year)) ^ N)

For a lifetime of 75 years:

P(terrorist kills you in your lifetime) = 1 - (0.999999 ^ 75) = 7.4997 x 10^-5

Which is 2 (a.k.a a couple) orders of magnitude lower than your 1 x 10^-3.

Comment: Re:We're so screwed. (Score 2) 237

When that next truck bomb detonates at a sporting event or mall, or when that next muslim fan goes on an indiscriminate killing spree through a church, know in your heart that you have allowed that to happen.

I'll enjoy my freedom, thankyouverymuch, even if it does come with an 0.001% chance of dying by terrorist.

0.001%? That's insanely high. The real rate is a couple orders of magnitude lower. It just goes to show how completely terrible human beings are at estimate the risk of extremely rare events.

Comment: Re:1000 times (Score 2, Informative) 622

by TheNastyInThePasty (#49529773) Attached to: Cheap Gas Fuels Switch From Electric Cars To SUVs

You don't need to have a crystal ball. The price drop only happened because Saudi Arabia wanted to assert its dominance in the global market. With higher fuel prices, North American companies were investing in more expensive extraction methods that only become profitable when prices are high.

Saudi Arabia has been keeping its production down to drive up fuel prices and decided that enough was enough. They didn't even ramp up production to full capacity and it's been causing oil companies in North America to shutdown sites and lay off workers. Once Saudi Arabia decides that the oil companies get the picture, they will cut production again.

Then, even when prices rise, investors will think twice about risking their money to support oil extraction.

Comment: Re:well.. (Score 5, Informative) 760

I think the point is not for the police departments to get Teh Phat Lootz, but to equalize the pain of violating the rules.

You can't have one without the other. Unless you deny the entire government the money from the fines, the rich will become the only ones targeted by traffic cops. It's already bad enough that police departments prioritize money over safety. It could perhaps become bad enough that the cops ignore anyone without an extremely nice car because the revenue is not worth it.

Movies

Gritty 'Power Rangers' Short Is Not Fair Use 255

Posted by timothy
from the wait-til-you-see-how-scully-revives-walter-white dept.
Bennett Haselton writes: Vimeo and Youtube are pressured to remove a dark, fan-made "Power Rangers" short film; Vimeo capitulated, while Youtube has so far left it up. I'm generally against the overreach of copyright law, but in this case, how could anyone argue the short film doesn't violate the rights of the franchise creator? And should Vimeo and Youtube clarify their policies on the unauthorized use of copyrighted characters? Read on for the rest.

Comment: Re:There is no legitimate reason to show it. (Score 1) 645

"Look at those evil Muslims killing innocent people to further their political goals! They are barbaric demonspawn! NUKE THE ENTIRE MIDDLE EAST!"

Of course, people with this view (I know a few) are completely unaware of the incredible irony...

Transportation

Why Didn't Sidecar's Flex Pricing Work? 190

Posted by samzenpus
from the you-get-what-you-pay-for dept.
Bennett Haselton writes Sidecar is a little-known alternative to Lyft and Uber, deployed in only ten cities so far, which lets drivers set their own prices to undercut other ride-sharing services. Given that most amateur drivers would be willing to give someone a ride for far less than the rider would be willing to pay, why didn't the flex-pricing option take off? Keep reading to see what Bennet has to say.

The life of a repo man is always intense.

Working...