NORTH  J532  3  J9653  K84  6  Q9876542  AQ  75    AKQ9  A  87  AQJT96    T874  KJT  KT42  32

Dealer: North    Vul: EW   MP Scoring West 1 31 4 North Pass Pass Pass Pass East 1 2 4 Pass South Pass Pass Pass Pass

1 6+ hearts, 7+ points

On North's diamond lead, West wondered of hopes for 6.
The ideal contract was 6.
If hearts had divided 2:2 or if the K had fallen singleton, two slams would have been missed in the one hand.
The odds of a 2:2 division of 4 cards are 40.7%.
Odds of a 3:1 division are about 50%. Of 3:1 divisions, 1/4 of the time the singleton will be any particular member: 1/4 x .50% = 12.5%
Combined, the odds of a heart slam making are about 53%, better than average.
There are other considerations that diminish that 53%, such as possible club ruffs on club leads and possible spade ruffs.

Many players will count the East hand as good enough for a 2 opener: 5 clubs, 3 spades and the A might represent "9 tricks", a 1/2 trick over the requirement.

25>   3.71 -11.0  3.71        4.57  3.71 -11.0  3.71              2.57      
       660  -100   650   ----  680   650  -100   650   ----  ----  620   ----