# given Standard deviation and sum of terms, Find Mean!?

• Nov 2nd 2009, 08:39 PM
emilychan
given Standard deviation and sum of terms, Find Mean!?
30 Patients treated for the same illness were given a new treatment. They were then asked to evaluate whether 5 symptoms H,L,P,T,V were made better or worse by the new treatment.

For each symptom patients used one of the five ratings:
2: much better
1: somewhat better
0: same
-1:somewhat worse
-2:much worse

Symptom:
H , Sum of 30 ratings of H: 12 , Standard Deviation of 30 ratings of H: 1.4
L , Sum of 30 ratings of L: 35 , Standard Deviation of 30 ratings of L: 0.69
P , Sum of 30 ratings of P: -33 , Standard Deviation of 30 ratings of P: 0.79
T , Sum of 30 ratings of T: -26 , Standard Deviation of 30 ratings pf T: 0.43
V , Sum of 30 ratings of V: 2 , Standard Deviation of 30 ratings of V: 0.89

Problem:
For the symptom whose arithmetic mean rating was closest to 0, approximately what was the arithmetic mean rating?

I know the symptom T's arithmetic mean rating was closest to 0,
But I don't know how to calculate the mean with the information given