How many lottery tickets would have to be bought for there to be a >=50% probablility that every single possible combination has been chosen?  Or for smaller numbers how many people would you need in a room for there to be a >=50% probability that every day of the year is one or more of these people's birthdays?  

If these numbers are too large then how many people/tickets would be needed that there is a >=50% probability that >=50% of the lottery tickets/birthdays have been chosen?

Assume that birthdays and lottery tickets are chosen at random and not bunched, and forget about leap years to keep things slightly simpler.

hi my names Jasmin I am 10.  I wondered whether the indents on a dice will affect the probability of rolling each number if you roll it millions of times.  I guess the weight of the dice is minutely different on each side and this might effect the number it lands on eg the one is slightly heavier because it only has one hole.  I hope someone can help...

The Schrodingers cat experiment says the cat is still dead and alive at the same time because whether or not the cat is dead or alive has not been measured. I may have misunderstood the experiment- but why doesn't the cat seeing whether or not the vial has broken count as a measurement, even if it is only the cat who knows. The experiment implies a difference between the cat's consciousness and that of the human, which of course there is, but what is this difference and how do we know about the cat's consciousness?

I was leafing through New Scientist when I came across a picture of Stephen Fry. At the same instant, Mr Fry's voice came out of the radio, trailing a programme he was about to do. Clearly it was a meaningless coincidence, but the odds against it must be very large. What I don't know is how to go about calculating those odds. How would you work it out?