Measure of dispersion, Range, Quartile Deviation (Part - 6) - Statistics, Mathematics, Class 11 Video Lecture

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measure of this question measure of
dispersion will help you know what is
whether especially it is the measure of
variability or spread or sky tons of
data it will tell you how scattered
details how variable it is what is the
maximum value or the minimum value so if
you see the center tendency was telling
you what is the center point Arena right
mean median mode was all these were
telling what is the center point of data
which has a maximum frequency or what is
the mean but is a more what's the
medians these things were getting the
center in is but lawn is a dispersion it
will tell you the measure of variability
or return how spread details now if you
see the center tendency and the
dispersion
both are contrast but they together will
give you that exact picture Peter
neither central tendency not dispersion
alone can give you the best figure you
need both both of these will give you
the exact figure so for a data what
we'll do then 500 is he will tell ok
this is a central tendency also can find
this catalyst so if we give we have this
catalyst and if we have the central
tendency if you have boot off center and
NC n scatterbrains using these two you
can they can give you the exact data
what we can interpret the data in a
better way using central tendency and
using this already measure of dispersion
we can interpret data in a better
we have types of depression dispersions
we have range
quartile deviation mean deviation and
standard deviation will explain this
just
you to be measure of dispersion is
nothing bad it is the measure of
variability or spread or scatter beds of
it is contrast it is exactly contrast it
contrasts with the central tendency but
send a tendency and means no depression
dispersion we combine both this tool it
gives a better idea of other we can
interpret data in a better way using
good measure of dispersion and send your
energy together what is range range is
nothing but maximum value minus minimum
value so for the same type you see we
have the same guy player one and player
two little guys player one player two
now if you see the range for player a
will come out to be you could use the
maximum value but it is an Indian value
to do minus 40 that is 4 similarly the
range for player B will come out to be
100 minus C critics so with only with
this data we can tell anything so if I
am told that range of player is 4 and
range of player is 50
I can't tell much but the only thing I
can tell is that this guy's consistent
if this guy is not consistent but I
can't tell whether it is good or bad so
if you have this data also that the
maximum mean is 50 median is 50 mode is
50 and range where is 4 and here range
is pretty fine so if you add this data
also then this data I can get a clearer
picture so if I am told that if I am not
having this data this is hidden from me
and if I am told that mean median mode
are 50 and range is hundred for this
player a and for player B and for player
a the range is for mean median mode is
50 I can tell that player is better
because here this guy is more consistent
and the runs are same correct
so only with this measure of dispersion
that is only with range it does not give
the clear picture but range with mean
median mode it gives a clear picture
correct
now adding quartile division it is based
on the lower quartile and after
the difference is called the inner
quartile and the different divide is
caught by two pi divided by two is
called semicolon here you see the
formula is quartile division is q3 minus
1 by 2 Q 3 is this value n plus 1 by 4
down and q3 is 3 into n plus 1 by word
so for the same data and find quite a
deviation and I will see both are
different so here Q 1 will be n is good
to 7 here 7 here 7 here 7 plus 1 by oh
that dump right at the second double
second term in the second um here we
have is what Ewing I'm 34 by Orion first
49 similarly Q 2 will be 3 into 7 plus 1
by 4 is equal to vi um the sixth term is
51 so this becomes will be correct now
for player B now if a player be human
again will be same 7 plus 1 by 2 F term
for the second term and second term here
is 25 and Q 3 is Christopher with Lee
will be again free into 7 plus 1 by 4 a
term this will be 6 term the sixth term
here is 99 so for player a player a QD
is equal to 51 - 49 that is q3 minus q1
by 2 correct the value is you buy to
look inspired for player B QD is nothing
where 99 minus 25 by 2 that is 70
or by dude that is 37 by for this ever
so we can see that the values are
different so here we can say that V is
equal to 1 and here you can say QT is
equal to what is the so with this data
also I can see that this is more
dispersed and this is less dispersed
that means this guy the first guy is
more consistent layer is more consistent
player B is not consistent so so q DS
quartile divisions are also similar to
range but the advantage here it it knows
the extreme values pijama these values
are ignored here if you see right so the
extreme few values are ignored the court
ID which it is better than negative some
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