Premium Bond Winner ?

Primrose

You should have suggested 6 1 5 2 4 3...
That might have fooled them ! 

Primrose

SandyN21 said:

Nice little surprise in this morning's post - after winning £225 this month, I received a letter to say I'd won £25 allocated because the original winner wasn't eligible to receive it. 😃

I suspect that is quite a rare happening but nice to know there's always a chance of it happening.

trust.no.1

A rare event in that I actually know someone who has recently won a large prize . Their holding is 13K held for around 2 years. They won a £50K prize.

Primrose

trust.no.1 said:

A rare event in that I actually know someone who has recently won a large prize . Their holding is 13K held for around 2 years. They won a £50K prize.

if I won that sum I,d be tempted to keep the knowledge to myself .  There,s are sadly too many people with a sense of entitlement these days  who think knowing somebody who,s won a sum of money means that all comers are entitled to a share of it.!  

mandarin6

Sorry still not convinced Ernie is completely random.  The following quote is from the Government website when Ernie 5 was introduced.

"Since 1970 the Government Actuary has undertaken independent and robust statistical testing to assess the randomness of each monthly draw. While it’s not possible to confirm absolute randomness ..."

I rest my case.

eskbanker

mandarin6 said:

Sorry still not convinced Ernie is completely random.  The following quote is from the Government website when Ernie 5 was introduced.

"Since 1970 the Government Actuary has undertaken independent and robust statistical testing to assess the randomness of each monthly draw. While it’s not possible to confirm absolute randomness ..."

I rest my case.

The emphasis in that phrase should be on 'confirm' - they not saying that it's not random, they're just saying that randomness isn't something that can actually be proved.  However, those monthly checks are the most realistic way of verifying that there are no observable patterns, etc, as explained at https://nsandi-corporate.com/media-resources/ernie

But how can you prove it’s all random?

The test of proving that ERNIE’s outputs are robust has long been discussed by experts in the field of randomness.

However, from the outset, engineers working in conjunction with – but exclusive of – the ERNIE programme have proven that the numbers created by the machine are unpredictable and follow no set patterns.

The original system to test ERNIE’s randomness was called Pegasus, designed by Dame Stephanie Shirley, who went on to be one of Britain’s greatest computer engineers.

Since then, as with ERNIE’s evolution, testing randomness has developed and is now managed by the Government Actuary’s Department (GAD).

Each month after the Premium Bonds numbers have been generated, they are sent securely to GAD who run a number of tests to identify whether the outputs are truly random:

• The frequency test – whether every possible character in each position of the Bond number appears as often as it should. 
• The serial test – looking at the number of times one digit follows another (for example the number of 3s coming directly after 7s). 
• The poker test – looking at the number of times that a group of characters generated consecutively contain four identical characters, three of a kind, two pairs, one pair and all different.
• The correlation test – looking for correlation between characters in two different Bond positions over a series of Bond numbers. 

ERNIE has never failed to be anything but random in every test carried out by GAD.

Turning it round the other way, what statistically meaningful evidence do you cite that you believe disproves randomness?

mandarin6

Somewhere in NSI archives which I read last year (will find again if I can and paste), they admitted that E4 was showing bias and was one of the reasons it had to be replaced. I've also discovered doing a quick trawl  that some bonds particularly those with PP as their letters have been drawn consistently each month. One lucky holder of a small bond won 25k two months in a row. I'm sure there are more examples but nothing will convince me that E5 isn't showing bias to certain letters.

masonic

mandarin6 said:

Somewhere in NSI archives which I read last year (will find again if I can and paste), they admitted that E4 was showing bias and was one of the reasons it had to be replaced. I've also discovered doing a quick trawl  that some bonds particularly those with PP as their letters have been drawn consistently each month. One lucky holder of a small bond won 25k two months in a row. I'm sure there are more examples but nothing will convince me that E5 isn't showing bias to certain letters.

Fortunately bias is easier to prove than randomness.

eskbanker

mandarin6 said:

Somewhere in NSI archives which I read last year (will find again if I can and paste), they admitted that E4 was showing bias and was one of the reasons it had to be replaced. I've also discovered doing a quick trawl  that some bonds particularly those with PP as their letters have been drawn consistently each month. One lucky holder of a small bond won 25k two months in a row. I'm sure there are more examples but nothing will convince me that E5 isn't showing bias to certain letters.

You do realise that randomness doesn't actuallymean evenness, i.e. the fact that some subsets will be luckier than others over a specific period doesn't indicate that the draw isn't random or that it's biased?  As with an example quoted earlier in the thread, it would be far more suspicious if every group of letters (or any other way of subdividing) came out evenly.

Likewise, 'bias to certain letters' is meaningless, as the bonds themselves aren't 'in the draw' as such but random numbers are drawn and then mapped onto bond numbers....

However, if you're caveatting your comments with "nothing will convince me" then it's clearly a waste of time discussing the facts!

mandarin6

Not sure I agree about how the numbers are drawn. NSI state each month before the draw we increase the range to include those numbers eligible for that months draw. Namely those numbers issued by that months draw. Therefore not as random as you think, someone is inputting information into E5.