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 77 25 Jun 2006 07:33

What are the odds?

I&#39;m trying to crunch numbers better and I am wondering what is the statistical (%&#39;s) averages when you re-roll hits/wounds? Eg. I know that having BS3 means that you hit 50% of the time, but what about TL weapons? How does that number change.

I have tried this before in previous posts and have run into differing numbers.

Just seeing if there is someone there that can lend a hand.

 Nuke 25 Jun 2006 08:37

Re: What are the odds?

Someone has a list of probabilities of rolls for a d6 and 2d6, I don&#39;t remember who, though.. might be on the main site.

-Nuke

 Pollo 25 Jun 2006 10:51

Re: What are the odds?

Quote:
 Originally Posted by Nuke Someone has a list of probabilities of rolls for a d6 and 2d6, I don't remember who, though.. might be on the main site. -Nuke
The article in question.

 Abanim 25 Jun 2006 17:30

Re: What are the odds?

Quote:
 Originally Posted by Pollo
That&#39;s a good article, but it doesn&#39;t address the problem of re-rolls, which was the subject of 77&#39;s query. I&#39;ll have a go at writing a quick explanation.

Okay, let&#39;s suppose that a broadside suit is firing its missiles, at BS3. You have the following possibilities:

Probability of a hit: [sup]3[/sup]/[sub]6[/sub] = 0.5
Probability of a miss: [sup]3[/sup]/[sub]6[/sub] = 0.5

Notice that the two probabilities sum to 1, like this: 0.5 + 0.5 = 1. This is important - it applies whenever you have two possibilities such that at least one of them must occur, but they can&#39;t both occur.

Now, let&#39;s say that broadside fires its twin-linked railgun instead. Rather than looking at the chance for it to hit, I&#39;ll try to work out the chance for it to miss, because that&#39;s easier to figure out. Now, for a twin-linked weapon to miss, you have to miss with your first roll to hit, then miss again on the re-roll.

Probability of a miss with the first roll: [sup]3[/sup]/[sub]6[/sub] = 0.5
Probability of a miss with the second roll: [sup]3[/sup]/[sub]6[/sub] = 0.5
Probability of missing with both rolls: 0.5 * 0.5 = 0.25

To get the probability that both events occurred (ie, that both rolls missed), I just multiply the probabilities together. So, the chance of missing with a twin-linked weapon at BS3 is 0.25. Now, remember what I said earlier about probabilities summing to 1? The chance to miss plus the chance to hit must always equal 1, like so:

(chance to hit) + (chance to miss) = 1

Therefore:

(chance to hit) = 1 - (chance to miss)

Since I&#39;ve already calculated the chance to miss, I can work it out:

(chance to hit) = 1 - 0.25 = 0.75

So the probability of hitting with a twin-linked weapon at BS3 is 0.75, or 75%. Is that clear enough? If you&#39;re not sure, try working it out for BS2 or BS4, and post your working so you can get some feedback.

 77 26 Jun 2006 04:48

Re: What are the odds?

This looks good and is very helpful.

Here&#39;s what I came up with:

For Regular weapons:
BS2 = 33% chance to hit
BS3 = 50% chance to hit
BS4 = 66% chance to hit
BS5 = 83% chance to hit

For TL weapons:
BS2 = 55% chance to hit
BS3 = 75% chance to hit
BS4 = 88% chance to hit
BS5 = 97% chance to hit

[hr]

This really helps for testing. Correct any of the math if it wrong.

 Abanim 26 Jun 2006 08:56

Re: What are the odds?

All correct! It looks like you&#39;ve got the hang of it.

 Wargamer 27 Jun 2006 10:16

Re: What are the odds?

There is one I&#39;d like to add... and that is Sharpshooters:

58.333% chance of hit.

For those who are interested, here&#39;s the "full" Bs table.

Bs 0 = 0.000%
Bs 1 = 16.666%
TL Bs 1 = 30.554%
Bs 2 = 33.333%
Bs 3 = 50%.
TL Bs 2 = 55.554%
Bs 3.1 = 58.333% [Sharpshooters]
Bs 4 = 66.666%
TL Bs 3 = 75%
Bs 5 = 83.333%
TL Bs 4 = 88.888%
TL Bs 5 = 97.222%

 alcibiates 27 Jun 2006 12:31

Re: What are the odds?

Excuse my ignorance, but I&#39;ve never heard of a sharpshooter. What are they?

 Wargamer 27 Jun 2006 13:19

Re: What are the odds?

It&#39;s a Doctrine available to the Guard.

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