Rahul - Shalaka - Punam - Alex
Weights and
heights are good examples of frequency distributions which "tend" to
become bell - shaped (normal distribution)
curves.
But try
plotting these curves for
. A family
of 10 persons
. 1000
people staying in same building
. Entire
population of the world.
You will
find that from an extremely SKEWED Curve (For family), you more to an extremely
CENTRALIZED (bell - shape) curve, as you
plot world's Population.
So, the
first thing about these curves is SAMPLE SIZE or POPULATION.
In the
enclosed graphs, our "Co - Professionals" populations (which we have
plotted) are relatively" small. If these were one million in each
case, we would have got a much smoother/ more centralized /less skewed curves.
Then again,
1000 people staying in same building. Surely that curve looks better than the
curve for 10 family members. Now you can make it look even better if you plot a
curve for height or weight of only those people (amongst those 1000) who are
. Of same
"age" (say 10 years)
It will
further improve if you plot
. Only
"Girls" of 10 years of age.
So, besides
sample - size (population), the smoothness / centralization of a curve has a
lot to do with
"Similarities amongst the member of the population"
i.e. "Apple - For - Apple" comparison Unfortunately, our "Populations" contain lots of "Dis - similar" persons !
i.e. "Apple - For - Apple" comparison Unfortunately, our "Populations" contain lots of "Dis - similar" persons !
eg.
"Banking/ Insurance" Professionals
If
. Your population was 100,000 people and
. You plotted a "Sub -
population" of
- Same Age
- Same
Experiences (yrs)
- Same
DEGREE
- Same Sub - Sector (Pvt. Vs. Public)
- Same
Region etc.
Then you are bound to get a much smoother /
centralized distribution where "extremes" of Raw - Scores have
very low probability of occurrence. Given this (theoretical) background, it will take a
very long time for our graphs to become NORMAL / BELL - shaped, when populations of each type of "Co -
professional's reach 100,000 or more.
Till then the graphs will look terrible at least to
people who do not have much exposure to statistics. It may even lead to disbelief / skepticism/ rejection of
the very concept !
We cannot
afford this.
May be "Cumu. Percentage Vs. Raw Score"
chart drawn by you in enclosed page is our answer.
It is simple
to understand (institute), which makes it ELEGANT.
No
"Mean"
No
"Standard Deviation (6)"
No Skew
(to confuse)
Just one
vertical and one horizontal drop are sufficient to tell the candidate.
. What is
my Score? (Raw Score)
. Where
do I stand ? (Percentile Score)
Amongst
my Co - profs
. How
many Co - profs. ? (Population)
This graph is not "Cluttered - Up" with
several lines or tabulations showing population between +10 & -10 (- which,
in any case, a candidate does not understand !)
I believe because of the concept of "Comu.
Percentage of Co - professionals. Vs "Raw Scroe",
The graphs (for any function / skill / any
population - size / any combination of age / exp/ education level /region etc)
Will
always come out as shown by you.
It will always (or almost always) be a smooth,
upward curve without "Kinks" - especially, if your RAW - SCROE
DATA TABLE, increases raw - scores by
1, i.e. 1, 2, 3, 4, 5 ......... 100
I suppose
Microsoft Chart, will automatically adjust the X axis and automatically
restrict it when "Percentile - Score" figure hits 100. Y axis will
always remain as shown by you.
Suggest you / shalaka quickly experiment with 10/15
other FUNCTION - SKILL populations to assure us that this concept will always
work, and that we are able to programmatically generate / drop the horizontal /
vertical lines as shown in enclosed sample graph.
You may want to adopt this concept also for
"SALARY GRAPH" (makes sense), what about TENURE GRAPH ?
I believe, this SIMPLIFICATION (-and avoidance of
statistical jargon) will attract the candidates.
Hemen Parekh
No comments:
Post a Comment