The Student Room Group

S1 Question Help

Hi,

I've attached an S1 gold paper. If anyone could help with question 4: d) and e) that would be a huge help - you don't have to do the question, but I don't understand the method behind the answer (which is also attached in the same file).

Thanks,
Tom
Original post by TomHibbs12
Hi,

I've attached an S1 gold paper. If anyone could help with question 4: d) and e) that would be a huge help - you don't have to do the question, but I don't understand the method behind the answer (which is also attached in the same file).

Thanks,
Tom


Ah, the (R) paper..

Whilst I haven't worked through the question, from memory, turner is 6 letters... the mean is also 6 (from memory...) so when you sum up to include the new term for Sxx, it's (old Sxx + (6-6)) = old Sxx.

** what may be key and hidden is that, if you add the value of the mean to a sample with the mean, then the mean remains unchanged.

Eg if I had a set 5 numbers that sum to 25, then the mean is 5.

If I add a 6th number which is the mean (I.e. 5) then the new total is 30 and hence the new mean is still 5.

This is then used in the definition of Sxx.
(edited 6 years ago)

Quick Reply

Latest