# When Only 80% Of Computers Having Viruses Is Considered A Good Thing

### from the ouch dept

The headline of this story sounded like good news at first, claiming: Fewer computers infected with virus. Then you read the details, and realize they’re saying that the number of virus infected computers in China has dropped from 88% to just 80% — and you have to wonder just what folks are doing there to have so many viruses. Given China’s ability to control so much of the internet in that country, you would think that part of those efforts would go towards trying to block viruses. Apparently not.

## Comments on “When Only 80% Of Computers Having Viruses Is Considered A Good Thing”

Sissy Pants says:

# Um Sony?

Well, considering the Sony rootkit has been “infecting” computers since 2004 the extent isn’t known yet… it’s not a huge suprise that 80% of china is infected…

What percentage of the US is infected? Or Europe? Are you?

Testudo says:

# Re: Um Sony?

I agree. Some viruses may not become appearent for a long time. Not all viruses are the headline grabbers that bring down entire computer networks within days

dorpus says:

# Confidence Interval?

I would want to know the 95% CI on that. There is the concept of Risk Function — mathematically, it is very difficult to prove whether a coin flip has a 50% chance of heads, or a 55% chance of heads.

To determine probability, our intuition may tell us to flip 100 times and count the number of heads, i.e. use the sample proportion. However, it can be shown mathematically that it is better to artificially add 3 heads and 3 tails to our counts, if we are confident that the true probability is close to 50%. Our estimate will be about 11% more accurate this way.

dorpus says:

# Re: Confidence Interval?

p.s. When humans flip a coin, they tend to place the head up before flipping, and everyone has roughly the same thumb strength, so a paper from Stanford last year showed that the probability of a coin landing heads is in fact roughly 55%.

Wyatt says:

# Re: Re: Confidence Interval?

Why not the 75% conf. interval? What’s so special about 95%? Would you not make a bet on a study that had had a 90% CI, what about 85%? Stats is stats… not truth.

antigone says:

# Re: Re: Re: Confidence Interval?

By using a higher confidence interval, you’re less likely to make a Type II error, which is a really stupid thing to make – to claim something is statistically significant when it isn’t. It’s like the commercial for the prescription for Detrol LA. When you actually look at the reports for it, the medication really didn’t do anything that was significant.

And the 95% CI is a typical cutoff for estimating unusual values.

spiker says:

# Re: Re: Re:2 Confidence Interval?

With all due respect I think you have type 1 error mixed up with type 2 error

dorpus says:

# Re: Re: Re:2 Confidence Interval?

Actually, that’s a Type I error, when you conclude that something is significant (when it isn’t). A Type II error will conclude the effect is insignificant, when in fact it is significant.

The probability of not making a Type II error, i.e. correctly finding significance, is known as “power”.

95% CI has been the gold standard for much of scientific research for many years. It’s saying that if we were to repeat the experiment at the same scale, we have a 95% chance of reaching the same conclusion. Here, the 95% is known as the “size” of the test. One can perform 90% CI in situations where the results are inexact, or 99% CI’s in situations that demand more precision.

NormL says:

# Re: Confidence Interval?

Why would you want to know? Why don’t you want to know at this point in time? What is causing this delay in your decision to gain the knowledge in which you seek?

# Preventing viruses requires education

Seeing as the Chinese government has done everything in its power to prevent their citizens from communicating with the free world, it should come as no surprise they are infected. They obviously have no clue how to prevent them. The great wall of virii.