2. RAW DATA
Mean= sum of the observations/ number of items
= Ʃx/ n
GROUPED DATA
Mean= Ʃfx/ N
where, N is the sum of frequency
3. MEDIAN
RAW DATA
Item of {(n+1)/2}th position
GROUPED DATA
Median= l+ (N/2-m)/ f x c
where, N= total frequency
m= cumulative frequency up to the
median class
f= frequency of median class
c= class interval
4. RAW DATA
Mode= observation most repeated
frequently
GROUPED DATA
Mode= l+ f2/ (f1+f2) x c
where, l= lower bound
f1= frequency of modal class
f2= frequency after the modal
class
c= class interval