I have come across a few calculations with the ? Sigma sign sign when studying for F2, I am using a casio fx-83GT Plus calculator and it doesn’t have this symbol how can I do these calculations?
Sigma is ‘shorthand’ for “sum of”, and I am sure your calculator will have a “+” symbol on it, which is all you need.
The only calculations with sigma in are those relating to regression and correlation, and if you watch my free lectures you will see precisely what it means and how to use the formulae.
(Our free lectures are a complete course for Paper F2 and cover everything needed to be able to pass the exam well.)