Limitation of mean deviation - Statistics Video Lecture - Class 11

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we have been here we have mode we have
range we have quater elevation we have
indications of all we'd have been
division about me you have so many terms
so that means this is chalk now but no
there are some limitation of main
divisions mean division is not always
true sometimes mean division is not able
to give us a clear picture and thus we
need some other form of mathematical
representation in the criteria let's see
for example so let's suppose we have to
sample our sample is this data - - - - -
- - second sample B is 3 1 3 1 - 3 1 - 3
- 2 samples now for both the sample mean
is 0 take the mean of this if you add
these all the value just becomes 0 by 0
is 0 this also becomes 0 by 0 0 so we
not for this family similarly mean
deviation about means in the beat is 0
mean division about mean for both a and
B see you can find this value if you
want so let's find me division about
mean body or a the mean is 0 so what we
have it reversed let's find this X so I
will write x I here X is minus 2 minus 2
minus 2 now I don't mind
Xie - 0 because 0 is the mean more this
becomes 2 minus 0 or this is also minus
2 minus 0 is minus 2 mod is - correct
now we have to find the mean division me
if they wish it about me so we add all
this 1 2 3 4 5 6 7 8 abo 16
sixteen and the number of doubles the
formula is Sigma X minus mean this value
because there's frequencies always one
for this by correct now let's do the
same thing for sample D this for e what
be administrate excites X is 3 1 3 1
minus 3 minus 1 minus 3 miles right here
also mean is 0 so we'll find X I minus 0
3 minus 0 mod is 3 1 minus 0 mod is one
3-0 count is 3 this is 1 minus reminds
us you know mod is over 3 because when
does 3 minus 0 is minus 3 minus B mod is
3 minus 1 minus 0 modulo 1 because minus
1 minus 0 is minus 1 and minus 1 mod is
minus 1 this is could you add this this
becomes 4 8 16 House of M is going to be
way way formula MD here will also be
Sigma X I minus M 1 right and this is
nothing but 16 back so you see both the
case mean is same we get the same also
mean deviation about when you say mean
division about median result mean the
about minion minion see so that means
mean division about mean is not always
sufficient to represent data so what we
do that's cup thank you
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