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Use of Sxx in Edexcel Alevel Maths

Do i have to use Sxx in Statistics or can i get away with not. I don't remember being taught it but its in the formula booklet. What questions are there on this?

Reply 1

mqb2766

Original post

by rehelpme

Do i have to use Sxx in Statistics or can i get away with not. I don't remember being taught it but its in the formula booklet. What questions are there on this?

It can be used to calc the variance (standard deviation).

Reply 2

rehelpme

Original post

by mqb2766

It can be used to calc the variance (standard deviation).

ok but its not something we'll be asked to calculate? its something we'll be given to calculate variance using Sxx/n?

Reply 3

mqb2766

Original post

by rehelpme

ok but its not something we'll be asked to calculate? its something we'll be given to calculate variance using Sxx/n?

The usual is that youre give something like Sxx and Sx (or the mean), or similar, and asked to calc the variance (standard deviation). To calc Sxx from a data set is tedious, but it could be asked.