This is a whole lesson on looking at combining data sets, in particular combining the mean and standard deviation. It comes with a starter, learning objectives, different small activities to assess understanding, lots of examples, and plenary. The strength of this resource (16 slides) is the excellent examples and teaching content.
When looking through my files I couldn't find a particularly great worksheet or activity on this, so I have included a mixture of things that I had already, which have some good questions in. I looked through various textbooks I have and the best I saw was the Cambridge one, but again it only had a few really good questions in.
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