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Broken Cyberware—too bad

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Feb 1 2008, 02:49 AM

Post #26

Moving Target

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QUOTE (Kagetenshi)

Slightly over 66% of the time, yeah. I don't really think that counts as acceptable for something like flying a transport or passenger aeroplane, though.

I need some maths tutoring. When I'm working out rough probabilities in SR I reckon that 6 dice at a TN6 gives a 6 in 6 chance so a probability of 1. 3 dice at TN6 gives 50% and so on. Is this correct?

As for the tests, autonav usually gives 2-3 dice so a proficient driver (skill 3) can get 6 dice easily enough. Some of the driving test modifiers seem off too. +1 to 3 for stressful situations, the rules say only tests in extreme situations which inevitably would be stressful. Large vehicle of type gets a penalty which it seems is covered by handling being worse for larger vehicles etc.

Kagetenshi

Feb 1 2008, 03:14 AM

Post #27

Manus Celer Dei

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QUOTE (Link)

I need some maths tutoring. When I'm working out rough probabilities in SR I reckon that 6 dice at a TN6 gives a 6 in 6 chance so a probability of 1. 3 dice at TN6 gives 50% and so on. Is this correct?

Not quite. Think about it this way: by that reasoning, 9 dice gives you a 150% chance of success ;)

What you're calculating is expected successes, which is much faster to calculate but can be deceptive. You do expect one success from six dice, but the actual probability of it is only in the mid-60s. It's still expected—more than 50% chance of at least that, and (more importantly) about a 40% chance of exactly that many successes (more than any other number of successes), but it's not overwhelmingly (or even highly, for some definitions) likely.

Expected with low certainty.

~J

mmu1

Feb 1 2008, 04:05 AM

Post #28

Running Target

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QUOTE (Link @ Jan 31 2008, 10:49 PM)

QUOTE (Kagetenshi @ Jan 31 2008, 06:03 AM)

Slightly over 66% of the time, yeah. I don't really think that counts as acceptable for something like flying a transport or passenger aeroplane, though.

I need some maths tutoring. When I'm working out rough probabilities in SR I reckon that 6 dice at a TN6 gives a 6 in 6 chance so a probability of 1. 3 dice at TN6 gives 50% and so on. Is this correct?

As for the tests, autonav usually gives 2-3 dice so a proficient driver (skill 3) can get 6 dice easily enough. Some of the driving test modifiers seem off too. +1 to 3 for stressful situations, the rules say only tests in extreme situations which inevitably would be stressful. Large vehicle of type gets a penalty which it seems is covered by handling being worse for larger vehicles etc.

The chance of getting at least one success on a given number of dice is 1 - (the chance that you'll roll a failure on all the dice).

In this case, it's 1 - (the chance that you'll roll 5 or less on all 6 dice) which is 1 - (5/6*5/6*/5/6*5/6*5/6*5/6), or ~ .66. (The chance of not getting a 6 on 1d6 is 5/6 - the chance of rolling again and also not getting a 6 is still 5/6, so the chance of failing to get a 6 twice in a row is 5/6*5/6 - 25/36... same idea with six in a row, you just keep on multiplying)

Stahlseele View Member Profile	Feb 1 2008, 10:06 AM Post #29
The ShadowComedian Group: Dumpshocked Posts: 14,538 Joined: 3-October 07 From: Hamburg, AGS Member No.: 13,525	and i still stand by my decision that the probability to roll a success is 50% . . either a success comes up or no success comes up <.< . . you can probably guess that i am not too fond of too much math g

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