# Black dice probability question

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The magic of probability is beyond me but I'm sure this is a very easy question for someone else.

Assume an attack from a single arc with only black dice in range. At what number of black dice does it become more effective to have Ordnance Experts to re-roll misses than to add more black dice with External Racks.

This is a question aimed at RitR ships with only one upgrade to start. I realise that OE has other benefits like it can be used on both attacks and over repeated turns and so on. But what if you were only expecting to get one attack?

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8 hours ago, Plessiez said:

The magic of probability is beyond me but I'm sure this is a very easy question for someone else.

Assume an attack from a single arc with only black dice in range. At what number of black dice does it become more effective to have Ordnance Experts to re-roll misses than to add more black dice with External Racks.

This is a question aimed at RitR ships with only one upgrade to start. I realise that OE has other benefits like it can be used on both attacks and over repeated turns and so on. But what if you were only expecting to get one attack?

OE increased the average output of a black die by 0.25, from 1.00 to 1.25

Ex Racks without rerolls add 1.0x2=2.0

But that's a single attack, so OE can add more dmg over the course of a game, easily.

But really, why would you not do both?

And that's before discussing how OE can improve your chances of landing a coveted black crit, if you have APT/ACM.

Edit: 8 die rolls is the answer. That's break even.

Edit: corrected my idiot maths.

Edited by Green Knight

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1 minute ago, Green Knight said:

Edit: 6 die rolls is the answer. That's break even.

Thanks! I think you missed the bit where I said this was a question aimed at RitR builds with only one upgrade to start.

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You need to be rolling around 4 black die a turn for OE to have benefit.

I used my gut instinct to determine this number. Average damage and applied damage are not the same. Average damage is largely meaningless, Applied damage is everything.

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I thought black dice had an ave. 1.0 dmg, with a probability to hit of 75%(due to having 8 symbols  on 8 faces, even though there isn't a uniform distribution of damage results on the dice faces (ie 2 sides blank and 2 sides with hit/crit combo)

(FYI:Red is .75 ave and 63% hit probability, Blue .75 ave, 75% hit probability.)

So: 50% for 1, 25% for 2, 25% for 0, then reroll the blanks with OE which then runs through the same probability again,  and leads to an expected 1.25 ave damage.

So in effect I think 4 black with OE re-roll should typically result in approx 6 damage (+/- 1).

Also, 6 black dice without a reroll should result in 6 damage (+/- approx. 1).

The first difference is that OE work on every attack (whether you roll 2 or 4 dice from the front or side of your Gladiator), (or on flack, which is also good).  (So even just expecting 1 attack [which seems cautious, I'd try to get 3 with black dice] I'd look to future proof the dice and go OE).

To answer the question behind the origin of the question, I would also go with OE over Exracks at the beginning of the RitR Campaign.

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1 hour ago, Cap116 said:

To answer the question behind the origin of the question, I would also go with OE over Exracks at the beginning of the RitR Campaign.

Depends on the ship, no?  If taking an Imperial Raider, which can only be counted on for one REALLY good close-range attack...and you'll get the ship (and upgrade) back every match without (much) cost in RitR...ExRack pays off quite quickly.

For things that might survive the match...and yeah, as suggesting, anything with black-dice flak...OE does work better.

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44 minutes ago, xanderf said:

Depends on the ship, no?  If taking an Imperial Raider, which can only be counted on for one REALLY good close-range attack...and you'll get the ship (and upgrade) back every match without (much) cost in RitR...ExRack pays off quite quickly.

For things that might survive the match...and yeah, as suggesting, anything with black-dice flak...OE does work better.

Honestly, for the difference of 1 point, I'd start with OE, even on a Raider, it'll help with flack, and if it gets 2 anti-ship shots off it'll equal the damage of 1 anti-ship shot that had ex-racks and the front arc.  Plus there are 3 ORD upgrade spots (one is the Ring of Kafrene, which is also a border region) and there only 2 Weapons teams spots.

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1 hour ago, Cap116 said:

and there only 2 Weapons teams spots

Which, thanks to the near-mandatory use of OE alone on anything with ordnance, will be in higher demand later.  This is good advice.

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