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Err this was meant for tactics not sure how it got here in army lists lol, my bad ><


I'm sure this has been discussed before - Math Hammer on Plague Marines vs Space Marines, close combat or bolters.. Is it really 2-3% chance to kill a PM or am I doing the math wrong somehow ??

1 SM attack on a PM = .5 chance to hit * .33 chance to wound * .33 chance to fail save * .5 chance to fail FNP = .027 (3% rounded)

This would mean you would generally need between 33-50 space marine attacks to kill one plague marine (2% = 1/50, 3% = 1/33), doesn't ever seem that way on the field though ;\

And on the other hand it's a 8% chance to kill a SM by a SM attack ?

1 SM attack on a SM = .5 chance to hit * .5 chance to wound * .33 chance to fail save = .082

So this would mean you'd need about 12-13 space marine attacks to kill one space marine (8% = 1/12.5), sheesh glad I picked plague marines ;D

It works a lot better when doing the numbers to keep them in fractions.

Killing a Plague Marine with WS4 S4 attacks:
1/2 hit * 1/3 wound * 1/3 fail save * 1/2 feel pain = 1/36 expected Plague Marine kill per WS4 S4 attack.

Killing a Space Marine with WS4 S4 attacks:
1/2 hit * 1/2 wound * 1/3 fail save = 1/12 expected Space Marine kill per WS4 S4 attack.

So, 36 attacks to get to one expected Plague Marine kill, vs 12 for a marine.

Plague Marines absorb three times as many S4 AP4 (or worse) attacks as normal marines. The advantage lessens as you move to higher strength or high AP/power weapons; a Power Fist kills both identically.

Lowinor wrote:It works a lot better when doing the numbers to keep them in fractions.

Killing a Plague Marine with WS4 S4 attacks:
1/2 hit * 1/3 wound * 1/3 fail save * 1/2 feel pain = 1/36 expected Plague Marine kill per WS4 S4 attack.

Killing a Space Marine with WS4 S4 attacks:
1/2 hit * 1/2 wound * 1/3 fail save = 1/12 expected Space Marine kill per WS4 S4 attack.

So, 36 attacks to get to one expected Plague Marine kill, vs 12 for a marine.

Plague Marines absorb three times as many S4 AP4 (or worse) attacks as normal marines. The advantage lessens as you move to higher strength or high AP/power weapons; a Power Fist kills both identically.

Ah nice that helps a lot.

How do you suppose you would add a single power fist or a few into the equation ? On either plague marines or space marines.

I can find the results using %'s yet again, but how would ya do it with fractions?

never realised how tough they were 0_o
i think ill stick to fex charing them lol

PF?

1/2*5/6*1*1=5/12

(Hit)*(wound)*(No Save)*(No FNP)

So you've got a 400% increase for SM, and a 1400% for the PM.

i think if i have to play a nurgle army i will be taking 3 tooled up fex's.

Never mind I figured it out, it's fairly easy.. But has to be done with "for instance" squads

Say there's a 10 man space marine combat squad with a single power fist

that's 9 marines times 2 attacks at 1/36 chance to kill a plague marine

(9/1 * 2/1) * 1/36 = 18/1 * 1/36 = 18/36 = 1/2

a power fist is 1/2 chance to hit * 5/6 chance to wound * no save * no FNP

1/2 * 5/6 = 5/12

5/12 * 2 fist attacks (on sergeant) = 5/12 * 2/1 = 10/12

so that's 1/2 PLUS 10/12 = 6/12 + 10/12 = 16/12 = 1 1/3 (133%) chance to kill a plague marine per turn with that squad

EDIT: Had my math all screwed up for a bit there haven't done math in a while ;D

beer, any hance of working out a fex's chances?
lots of D? in it though.

and thats a Str10 WS 3 fex, with D6+ 4 attacks, D3 Str 5 attacks.
would that complicate things?

Seems pretty damn hard to do but I'll give it a shot LOL, can't promise anything though ..

Are those d3 str 5 attacks extras? And I'm assuming it's a monsterous creature? ;D

yea, its a MC, and those D3 S5 are for its tail attack.

thanks lol, i thought this would be pretty hard to work out due to randomness and varying Str.

4+ hit (1/2) * 2+ wound (5/6) * no save * no FNP * 5-10 attacks

1/2 * 5/6 * (# of attacks)

5/1 = 25/12 = 2 1/12 (208%) Chance to kill one marine (but that's really 2 dead marines)
6/1 = 30/12 = 2 1/2 (250%)
7/1 = 35/12 = 2 11/12(292%)
8/1 = 40/12 = 3 1/3 (333%)
9/1 = 45/12 = 3 3/4 (375%)
10/1= 50/12 = 4 1/6 (417%)

Ouch! ::winces:: Hope I dont fight too many of those ..

Chance to kill one goes up 5/12 (about 42%) with each extra attack

4+ hit (1/2) * 4+ wound (1/2) *

1/1 = 1/4 (25%)
2/1 = 1/2 (50%)
3/1 = 3/4 (75%)

Assuming these are also MC they go up 25% with each extra attack

Now if only I could figure out howto do it as all one percentage ... Gonna hafta ponder that one ;P

Beerfiend wrote:4+ hit (1/2) * 2+ wound (5/6) * no save * no FNP * 5-10 attacks

1/2 * 5/6 * (# of attacks)

5/1 = 25/12 = 2 1/12 (208%) Chance to kill one marine (but that's really 2 dead marines)
6/1 = 30/12 = 2 1/2 (250%)
7/1 = 35/12 = 2 11/12(292%)
8/1 = 40/12 = 3 1/3 (333%)
9/1 = 45/12 = 3 3/4 (375%)
10/1= 50/12 = 4 1/6 (417%)

Ouch! ::winces:: Hope I dont fight too many of those ..

Chance to kill one goes up 5/12 (about 42%) with each extra attack

4+ hit (1/2) * 4+ wound (1/2) *

1/1 = 1/4 (25%)
2/1 = 1/2 (50%)
3/1 = 3/4 (75%)

Assuming these are also MC they go up 25% with each extra attack

Now if only I could figure out howto do it as all one percentage ... Gonna hafta ponder that one ;P

Someone correct me if I'm wrong please but I suppose I would just need to figure out the average between the extra attacks ..

That would be 25+30+35+40+45+50 / 6 for the regular attacks

225 / 6 = 37.5 = 38/12 = 3 1/6 (about 316% avg)

And an obvious average of 1/2 on the extra tail attack attacks

So all with regular and tail attacks the average's equation would be 38/12 + 1/2 = 38/12 + 6/12 = 44/12 = 3 2/3 (366%)

Close to 4 plague marines dead each turn O_O .. well doesn't matter if they're plague marines or not with that str and MC ;D

im starting to feel alot better knowing i can kill these things lol
thanks for all of the maths.

funny to watch them try and hit back against WS3, T8, W5, 2+SV

Edit: and with miama opponents suffer -1 to hit

Except that Carnifexes are T7, and that's only with an upgrade. Bonded Exoskeleton? Maybe it's Reinforced Chitin. Either way, any smart opponent's going to have 2 Plasma Guns and a PF in his Plague Marine Squad, so good luck dealing with that.

CK

sorry, my mistake on the T.

and the fex will strike before a PF, so just need to shoot the unit, then charge it with the fex.
or, throw some lictors ino it.


and how many PF attcks is that a turn? he will have to take off 5 wounds (which can be regenerated)

this is of course that the rest of your opponents army isnt there. plague marines will come with back up. in pure nurgle armies its likely that they will have rhinos, which can outrun your fex's, otherwise they will have stuff to kill them at range..

plague marines are good for surrviving light weapon fire and sitting on objectives. if your opponent has let a combat fex get that close to your squad without causing it any damage, they you probably won the moment you deployed.

you can kill everything in this game. the balance is not devoting too much resource to kill one thing over another. you can devote as much as you like to killing my PM squad, but in the mean time ill be blowing the rest of your army up with plasma cannon and blastmasters.

regwon, a fex isnt on its own ether, its easy to blow up a rhino with a barbed strangler or venom cannon.
and things like trygons can easily catch up to them.
even a winged tyrant can do that without any problems.

reg, i take 2 winged tyrants, 3 monster fex's, alot of raveners, warrior spam, 3 lictors, and alot of endless gaunts.
so even gunning down a fex per turn wont do much.
and with atleast 60 gaunts running at you i doubt you will shoot th fex behind them.

I'd just like to point out (no matter how unhelpful it actually is) that what you're calculating is actually the amount of expected kills, and not the percentage a marine has to kill another marine.
If you were trying to find out the chance a defined number of WS4 S4 have of killing a single marine model, you'd get a number below 100%. Even if you would define the number of attacks coming at the marine as something completely ridiculous, the percentage would not be 100%, but rather something like 99.999%, as there is always the possibility of rolling 100 's in a row, no matter how small that possibility is. As a funny side note, I count a chance of 1.53 x 10^-76%, so 76 zeros followed by 1.53 something for rolling 100 ones in a row, but I could be wrong. (That's 0.000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,153% approx. Yes, that's 76 zeros. I counted.)

Now, if you're asking me how the percentage a defined number of attacks has to kill a single space marine is calculated, I'd have to let you down. I've yet to take a mathematics course on the subject. :S

Sorry for that, now carry on.

I would like to start off by saying, what a great job everyone is doing in the maths department! well done!

Second: I play against a friend who has both PM and 1k sons and his sons last way longs then his PM's, maybe cause as an eldar player i like to guide and doom, or maybe i through way too much fire power they way (6 brightlances a turn, he has no tanks and i love the gun [model]) and prism too.

I would like to ask are 1k sons mathimaticly going to last longer than your plauge marine? coz in all the games i play with him it takes twice as much fire power to bring down the sons?

No plague marines will outlast 1000 Sons against everything that allows them to get a "feel no pain" roll. Since you are hitting the guy with 6 bright lances and a fire prism, he is not getting his "feel no pain" and you are wounding on a 2 and he gets no armor save. The only reason that the 1000 Sons are surviving at all is due to their invul save.

i still think a dakka fex will make a mess of a PM squad, PF or no PF.

Dakkafexes will do little to nothing to a PM squad - at least, the typical elite dakka fex. Maybe a single PM dead from a round of shooting. In close combat, they don't have enough attacks to really do too much, and the powerfist is likely to at least even the odds.

Now, the uber assault fex that you posted earlier, yeah, that will tear PM squads apart. This is why I make a point of ignoring Tyrants and dakkafexes to shoot at that one first with my plasma and lascannons. On a good day, I can drop one a turn - if not, then likely at least two turns of shooting, and not from the entire army. This is from experience, as I do play an all-PM army.

I mostly laugh at warriors and gaunts - gaunts bounce off my PMs and die most often, warriors can do reasonably but 3+/4+FNP usually means I don't care too much about their weapons. Stealers can be nasty, but the only things I worry about is rending, and usually that's only 2-3 per squad. Same with raveners - one bad turn of rending and they're gone from return attacks and no retreat wounds.

JD21290 wrote:i still think a dakka fex will make a mess of a PM squad, PF or no PF.

(doing marine kills in x/27, as that's the lowest denominator)

Shooting: 8 shots, BS3 (rerolled), S6 (rerolled). 8 * 3/4 hit * 8/9 wound * 1/3 fail save * 1/2 fail FNP = 8/9 expected plague marine kills.

7 plague marines, two plasma guns, power fist on champ, shooting:
4 plasma gun shots: 4 * 2/3 hit * 2/3 wound = 48/27 expected wounds (24/27 if the 'fex is in cover)
10 bolter shots: 10 * 2/3 hit * 1/6 wound * 1/3 fail save = 10/27 expected wounds

Total of 58/27 expected wounds out of cover, 34/27 in.

Assault:
'fex gets two attacks (and will never get a bonus attack from charging since the marines have defensive grenades): 2 * 1/2 hit * 5/6 wound = 5/6 expected dead marines

normal plague marines: 2 attacks each: 12 * 2/3 hit * 1/6 wound * 1/3 fail save = 12/27 expected wounds
Power fist: 3 attacks: 3 * 2/3 hit * 5/6 wound = 45/27 expected wounds.
Total of 57/27 expected wounds.

Charging:

Normal: 18 * 2/3 * 1/6 * 1/3 = 18/27
Champ: 4 * 2/3 * 5/6 = 60/27

Total: 78/27

Now, the dakkafex has a grand total of 81/27 wounds; 7 plague marines on the charge have an expected wound rate of just under that. A round of shooting in cover and a charge expects over four wounds on a three wound target; shooting out of cover and charging expects over five.

Even in the most advantageous situation for the dakkafex (sitting in cover and shooting, never getting to assault), the Plague Marines still do more expected wounds to a target with less total wounds.

Of course, this is to be expected since the Plague Marines as described above cost twice as much.

thanks lowinor.

now how about a heavy fex, tusked, regeneration, increaced WS and I, talons, crushing claws, toxin sacs, reinforced chichin, bio plasma attack, toxin miasma, bonded exo, extended carapace, scythe tail ect, the whole 9 yards on him.
nearly everyupgrade possile to gain an advantage, so round the 340 pts mark.
any idea what that would do if it charged into a unit of PM's?

Mr.Freeze wrote:I'd just like to point out (no matter how unhelpful it actually is) that what you're calculating is actually the amount of expected kills, and not the percentage a marine has to kill another marine.
If you were trying to find out the chance a defined number of WS4 S4 have of killing a single marine model, you'd get a number below 100%. Even if you would define the number of attacks coming at the marine as something completely ridiculous, the percentage would not be 100%, but rather something like 99.999%, as there is always the possibility of rolling 100 's in a row, no matter how small that possibility is. As a funny side note, I count a chance of 1.53 x 10^-76%, so 76 zeros followed by 1.53 something for rolling 100 ones in a row, but I could be wrong. (That's 0.000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,153% approx. Yes, that's 76 zeros. I counted.)

Now, if you're asking me how the percentage a defined number of attacks has to kill a single space marine is calculated, I'd have to let you down. I've yet to take a mathematics course on the subject. :S

Sorry for that, now carry on.

You can really look at it either way, as 36 ws4 s4 attacks to kill one plague marine or a single ws4 s4 attack being 1/36 (2.7%) chance to kill a plague marine. In order to determine the % by a certain amount of attacks you just add those attacks to the numerator. IE 2 attacks = 2/36 or 1/18, 3 attacks = 3/36 or 1/12, 4 = 4/36 or 1/9. Is that what you mean?

As for the 1.53 to the -76th power I have no idea how you figured that out but I'm impressed LOL, would have to ponder it myself.

Lowinor wrote:Shooting: 8 shots, BS3 (rerolled), S6 (rerolled). 8 * 3/4 hit * 8/9 wound * 1/3 fail save * 1/2 fail FNP = 8/9 expected plague marine kills.

Just curious what formula you use for "rerollables" ? I understand that with 4+ rerollable it's 1/2 * 1/2 of the remainder. But what about other stuff like 2+ where it's 5/6, or 3+ where it's 2/3?

JD21290 wrote:thanks lowinor.

now how about a heavy fex, tusked, regeneration, increaced WS and I, talons, crushing claws, toxin sacs, reinforced chichin, bio plasma attack, toxin miasma, bonded exo, extended carapace, scythe tail ect, the whole 9 yards on him.
nearly everyupgrade possile to gain an advantage, so round the 340 pts mark.
any idea what that would do if it charged into a unit of PM's?

Don't have my 'nids dex with me nearby. It would probably kill them pretty effectively if it got to assault; the problem is getting there without being shot up -- the dakkafex at the least has a reasonable shooting attack and isn't forced into assault with the Plague Marines. A full CC 'fex has to deal with its prospective target shooting and walking backwards, and less likely to get any cover due to its target not needing any and thus being more able to require the 'fex to move out of cover to get the charge.

Beerfiend wrote:

Lowinor wrote:Shooting: 8 shots, BS3 (rerolled), S6 (rerolled). 8 * 3/4 hit * 8/9 wound * 1/3 fail save * 1/2 fail FNP = 8/9 expected plague marine kills.

Just curious what formula you use for "rerollables" ? I understand that with 4+ rerollable it's 1/2 * 1/2 of the remainder. But what about other stuff like 2+ where it's 5/6, or 3+ where it's 2/3?

Basically, it's just the probability of the roll (the initial roll), plus the chance of a successful reroll, which is the probability of the initial roll failing times the probability of the initial roll. For a probability p, this is p + ( p * ( 1 - p ) ), which simplifies to 2p - p^2. Ends up being 35/36 for 2+, 8/9 for 3+, 3/4 for 4+, 5/9 for 5+, and 11/36 for 6+. For a quick approximation on the table, rerolling x+ is pretty similar to rolling (x-1)+; a 3+ rerolled is pretty similar to a 2+, etc.

One screwy stat thing to keep in mind is the difference between averages and probability. If you look at 9 marines shooting at other marines (rapid fire range), you get a situation that maths out like this.

9 marines * 2 shots each = 18 shots

18 (#of shots) * 2/3 (chance to hit) * 1/2 (chance to wound) * 1/3 (chance to fail armor save) = 2 dead marines

This is the average number of marines that you will kill. However, what is the chance that you will kill 2 marines? The math is rather complicated, but the chance of killing exactly 2 marines is 28.7% and the chance of killing at least 2 marines is 61%. This is all calculated out using the binomial distribution. So you can see that the average (or expectation) number is a good way to look at things but don't confuse it with % chance of doing something because that's not what you are calculating.