We don’t normally post school based maths and stats resources directly on the ICSE site, for them you should hop along to CensusAtSchool.org.uk, but over the weekend I re-discovered a news story and NCETM resource on the probability of double-yolk eggs, after finding a double-yolk myself at breakfast sparked the memory.
An original UK news story featured in the Mail, google it if that link is outdated. You can then view the excellent NCETM resource (as a PDF) from their website (link below).
The resource takes information from Professor Sir David Spiegelhalter’s blog, again you can google this if the link is outdated. The explanation also featured on the BBC Radio 4 programme More or Less, that if you do not follow you really should. The explanation would be an excellent followup to the lesson itself.