smerriman

[hv=https://www.bridgebase.com/tools/handviewer.html?s=SAKT932HA6DJT62C2&n=HK8752DK975CKQJ8&d=s&v=s]200|300[/hv] South dealer, IMPs. Various questions on this hand and similar ones. Do you want to be in 3NT on these hands? Does North have a game forcing response to 1♠? If the answer to the latter is no, increase North's strength slightly so the answer is yes. How do you get to 3N when that's right, and 5/6D when that's right for various strengths of South with this shape?

Thanks, Rainer. I stand corrected.

Taking best hand into account, my calculations for 95% confidence are: South: (174.1,228.3) Other seats: (182.1,237.4) Multiple voids amongst South/West/North only: (28.7,53.8) All those numbers lie in these ranges (if anything slightly below average, but not significantly enough).

I didn't misread anything; I'm not sure what you think I did. As mentioned above, I am disagreeing with your estimate of opener being able to make the correct response to an invite on 2/3 of the deals opposite this particular hand. You say it is conservative with no evidence of why. My example was that unless you are declining the invite on some maximums, you're already below 2/3 on those cases, so have ground to make up on the harder cases. Even the hand that you said you would accept on - ♠Kxx ♥Ax ♦xxx ♣AKQx - requires getting the trump suit right, so while you would like to be in game on that hand, it's not contributing 100% to your success rate, only the 58% of making, dragging down your average further from the 2/3 mark. My original numbers - while perhaps not the best approach to accepting - resulted in opener making the correct decision 57% of the time, but that wasn't sufficient to make inviting worthwhile. It seems vsmague's acceptance criteria were not sufficient either. Are you able to provide acceptance criteria that actually work to support your hypothesis? Perhaps you meant that 2/3 of the time, opener will be able to decline "bad" games and accept "good" games. Sure, that might be achievable, but you're not beating the passers on all of those occasions; the number of times you go down in a "good" game contributes heavily to the final results.

I doubt your numbers as well. Even if opener has a 17 count, game is making less than two thirds of the time, so I am extremely skeptical that you could achieve a 2/3 success rate over all of opener's hands. I would expect a reasonable success rate opposite a "normal" invitation, but lower opposite this particular one.

Just to reiterate though, you're looking at the wrong numbers in terms of deciding whether to actually invite in this situation.

This is completely incorrect statistically. With such a tiny sample, a standard 95% confidence interval would be [4.16,15.03]. You would only be able to claim - and of course, not prove, since it can still happen 5% of the time - there is evidence of non-randomess if your average fell outside this range. Anything inside the range fits the null hypothesis that there is no bias. Again, completely inconsequential statistically. I was referring to the two prior to all of the ones you've listed. As of course, you only started measuring voids because you suddenly noticed a lot of them in one tournament; before that you were focusing on something unrelated (and also incorrect). Choosing when to start measuring heavily biases the results.

To top things off, guess how many voids you saw in the two Robot Rebate tournaments before the two you started reporting? 1 and 1. Below average. Bet you didn't pay much attention to those.

Now you're just making things up. I checked #5170, and there wasn't a single board that had two voids. You had a typo; you meant #5519. 4 voids is not uncommon; it happens on average about once every four tournaments, and you're finding it surprising. Even 5 voids isn't strange; the chance you've seen a 5 void tournament over 4 tournaments is about 36%. And you only need to play 3 tournaments to make it more likely that you've seen a deal with 2 voids than you haven't. You're just making yourself look silly now.

It actually turns out to be the other way around: *Given* no superaccept (beancounter), pass wins 35.9% and loses 30.3% *Given* no superaccept (your definition), pass wins 34.9% and loses 31.4% I guess it's a lot of the max 3 card supports that are weighing in. But passing is still a clear favorite for both.

You're making similar mistakes as last time. The probability a *given player* (eg South) has a void is about 5%. The probability at least one of the four players for a given deal has a void is about 20%. Over 36 boards, the probabilities of seeing a total of x voids (approximately): 0: 0.1% 1: 0.5% 2: 1.8% 3: 4.2% 4: 7.8% 5: 11.4% 6: 13.9% 7: 14.8% 8: 13.6% 9: 11.0% 10: 8.2% 11: 5.5% 12: 3.4% 13: 1.9% 14: 1.0% 15: 0.4% All of 5, 6, 7, 8 and 9 voids occur over 11% of the time, so aren't unusual in the slightest.

Rainer's numbers surprised me, so I ran my own 1000 hands to compare. I got slightly different figures for North declaring in spades (and the opposite conclusion): 10 or more tricks on 46.9% of hands 9 or more tricks on 84.2% of hands 8 or more tricks on 96.7% of hands Under the assumptions that: North will accept an invite with any 16+ HCP North will superaccept with 17 HCP and 4 spades: and comparing transferring and passing with transferring and inviting: 2.5% of the time, opener superaccepts (excluded from cases below) 15.8% of the time, we take 8 or less tricks, so passing wins 19.2% of the time, we take 9 tricks, but opener accepts an invite, so passing wins 17.2% of the time, we take 9 tricks, but opener rejects the invite so it doesn't matter 15.8% of the time, we take at least 10 tricks but opener rejects an invite, so it doesn't matter 29.5% of the time, we take at least 10 tricks and opener accepts an invite, so inviting wins This means passing the transfer is better than inviting with 3♠ - it wins 35% of the time, and loses 29.5% of the time. (This sim doesn't take into account upgrades - ie allows North to have 17 counts with a good 5 card suit and no 14 counts - but of course, adjusting for that makes North weaker, so would be more in favor of staying low.)

Yeah, not saying it *should*, but it's standard GIB and they'll never change it.

1♠ promises 8 HCP. You're "guaranteed" to have the king of clubs, so throwing the ace doesn't matter.

IJS are good. GIB's lack of understanding of when to actually use them is bad.

4NT is described as 20-21 points. GIB values its hand as 16 points, adding 3 for the void. Basic GIB does nothing more than add those two together and figure that's enough for grand.

As mentioned, the probability at least one of the four players has 5 of 24 "1%" hands (by your definition) is 9%. It's not "normal", but it will happen regularly enough, so having it happen definitely doesn't mean anything odd is going on. If you don't understand why, try this calculator: https://stattrek.com/online-calculator/binomial.aspx The probability of a '1%' hand is 7%, since there are so many '1%' distributions. Fill in 0.07, 24 trials, 5 successes, and you'll see P(X>=x) = 2.3%. Then for this to apply to all four players is 1 - (1-0.023)^4 = 9%. (Not this isn't 100% accurate due to the lack of independence, and my calculations earlier were more accurate, but they're close enough).

Yikes. mlbridge, you have a serious lack of understanding of statistics. Your definition of "about 1%" seems to be 1.326% or lower. On a single hand, the probability you are dealt a distribution which is "about 1%" or lower is about 7%; the sum of all of the low probabilities. In a 12 board tournament, a given player will be dealt two or more "about 1%" hands 20% of the time. Not abnormal at all. Over 24 boards, a given player will be dealt 5 or more "about 1%" hands about 2.3% of time. The fact that it happened doesn't mean the deals aren't random. But wait, this isn't what you measured. Why did you choose North? Was it perchance because you happened to notice that North had some distributional hands, and you didn't pick South because, whoops, that wouldn't have supported your theory? In a 12 board tournament, the probability you will be able to find a player with 2 or more "about 1%" hands is about 58%. That's right it's actually more likely this will happen than it won't. Over 24 boards, you'll be able to find a player with five or more 1% hands 9% of the time. It would be extremely unusual if you *didn't* notice such things happening.

OK, let's put this to bed once and for all. I just grabbed the last 2000 challenge-a-robot hands from BBO. Handviewer URLs, one per line, are in the text file uploaded here (with names removed for privacy). Claim 1: 5-0, 4-1 distribution is found more often than 3-2 Over the 2000 hands, there were 1233 instances (can be more than one per deal) of North/South holding an 8 card fit. The breaks were: 5-0: 1.78% 4-1: 13.06% 3-2: 34.14% 2-3: 33.98% 1-4: 15.09% 0-5: 1.95% Result: completely false. Claim 2: Qx after KJxx is 90% true Over the 2000 hands, there were 589 occasions of North or South holding KJ and an opponent holding the queen. The queen was onside on 52.3% of those occasions (margin of error 4%) Result: completely false Claim by other people: BBO deals are more distributional than they should be. South's hand over the 2000 deals: 4-4-3-2 - 20.75% 5-3-3-2 - 16.15% 5-4-3-1 - 13.25% 4-3-3-3 - 10.3% 5-4-2-2 - 9.75% 6-3-2-2 - 6.2% 6-4-2-1 - 5.3% 6-3-3-1 - 3.15% 5-5-2-1 - 2.85% 7-3-2-1 - 2.65% 4-4-4-1 - 2.25% 5-4-4-0 - 1.25% 6-4-3-0 - 1.2% 6-5-1-1 - 1.1% 5-5-3-0 - 1.05% 6-5-2-0 - 0.75% 7-4-2-0 - 0.6% 7-4-1-1 - 0.55% 7-3-3-0 - 0.3% 7-2-2-2 - 0.25% 8-3-2-0 - 0.1% 8-4-1-0 - 0.05% 8-2-2-1 - 0.05% 7-5-1-0 - 0.05% 6-6-1-0 - 0.05% 9-2-2-0 - 0.05% This lines up with the table here very nicely. Result: completely false.

Read the responses to your last two threads. Posting the same thing three times, and making up numbers with 0 evidence, is silly.

[hv=https://www.bridgebase.com/tools/handviewer.html?s=SAQJT93HT9D5CT752&d=n&v=o&b=17&a=1CP1SP2DP]200|300[/hv] You are playing the standard reverse system described by mikeh in the primer on reverse bidding. 2♠ is a 1 round force, and could be made with a dead minimum with 5 spades, or game forcing hands. Does it deny the ability to make a positive raise of one of opener's suits? Ie, would you bid 2♠ here, or 3♣? Which one gets this type of hand across better? In the primer, mikeh had a good 5 spade suit and 3 card minor support, and chose the club raise, and I've always assumed 2♠ would deny the ability to do so. But now I'm not sure, since if opener makes a nonforcing response of 2NT or 3♣ over 2♠, you can still bid clubs as a GF. But would opener take this as preference rather than a real club suit? Conversely, if you bid 3♣, are you going to be able to describe your spades accurately later? (If you consider this not good enough to make a 3♣ bid, add an extra jack or whatever.)

No, three diamonds (click Next to see the play).

[hv=https://www.bridgebase.com/tools/handviewer.html?nn=Human&n=ST874HAKQ76DJ7C62&en=Robot&e=SK5HT98432D93CQ43&sn=smerriman&s=SAJ2HJ5DA64CAK875&wn=Robot&w=SQ963HDKQT852CJT9&d=s&v=o&b=17&a=1C2D(Aggressive%20weak%20jump%20overcall%20--%206+%20%21D%3B%204-9%20HCP)2HP3DP3HP3NPPP&p=DKD7D3D4DQDJD9D6DTS4H4DAHJS9H6H2H5D2HKH3HAH9C5D8HQHTC7D5S7S5SJSQS6S8SKSACACJC2C3S2S3STC4C6CQCKC9C8CTH7H8]400|300[/hv] When West showed out on the first heart, it seemed like my only hope was East holding KQ of spades. On running the hearts I was surprised to see robot West throw all three diamonds, allowing me to make the contract. But afterwards, I was even more surprised to see that the contract is unbeatable - West is subjected to an extremely interesting squeeze without the count, with East under pressure also (at risk of being thrown in with the king of spades if he doesn't fly with it). Does this have a name, and is it actually one that declarer should get right if a human made some less obvious discards?

From a non-advanced point of view, I see no reason for me bidding this any different to as if South opened 1N. 2N - 3♦ 3♥ - 4♦ (natural second suit) 4N (no support for either) - 6N

A cue-bid definitely doesn't promise a fit in hearts here.