Statistic

[sadness]

My professor give me short question to answer for the lab. Does anyone know what he meant by location(center), variation(spread), and symmetry???? Any help will be appreciate it.

[sunkiss]

1. location (center): does that have to do with mean or median of the data points??
2. variation (spread): can be range {largest-smallest value}, or variance [or standard deviation]....there's a formula for finding that...but i cant put it on hea...pretty confusin.. somethin like this....
S^2= [sum of (x-mean)^2]/ N-1
x- all points,
N- # of points
3..symmetry..im not sure wat he's talkin bout...
....i hope i gave u some kind of help...hopefulli didnt confuse u or nethin..hihi....i just had lab with almost the same things dealin with statistics..lol =) good luck!

...this is formula for the variance (S),..to find the standard deviation...u take the square root of that

[Chris-T]

Statistic is a study to show/explain the data from large sample or
the whole population of data. There are 3 major characteristics
that can be used to describe any (most) population (or sample) of
data: central tendency (location, center), variation (spead, how far
from center), and the shape (of the distribution).
(1) Location, or center are mostly calcuated by "arithmetic average"
(or Mean) or by "Median". Note that Mean is calculated by taking
the average (sum of all data devided by number of data sampled), while
median is the "value" of the center/mid-point location (i.e. sample of
21 data, then the median is the data/vulue at the location "11" or
center of the data sorted in increasing order). Some statistic prefers to
use Median over the Mean. (Math, engineering, science..) used Mean
more often, while Economic, Business use Median more often. Reason
is for large random data, there are some very high/low data that
contribute to the mean (shifted), while Median is independent to
thr value (only location used). Ex: Housing Price (use Media)... due to
some house are very High (multi-miliion $) that would shift the average
to become scary or un-realistic report.
(2) Variation: once the Central is known, another importancc about the
sample/population is the Variation. It's the measure of How close/far
from the "center" the whole sample/population are. It would tell us
how wide or narrow the overall distribution. The higher the variation,
the wider the disribution (or data/sample are pretty scatter apart).
Typical parameters used for variations are "variance" and "std-deviation"
that go with the "mean/average". While the quartile (i.e. 25%, or 75%
or 10%-90%) are used with the Median (i.e. SAT, ... use Median and
percentile for reporting score statistic). Of course, Min & Max, range are
used for both approaches.
(3) The third key characteristics of distribution is its shape. While most
common known are Bell shape (which is normal distribution, and also
symetrical). Some random sample are not normal/symmetry (i.e. housing
price statistic may have normal at close to center/median price, while
very high price contribute to non-symmetrical shape). Non-symmetrical
shape are classified as either skew (left, or right as in housing price ex).
The shape can mostly be observed with graphical method & are widely
used in all media when reporting statistic figures.

[yeudoi]

Symmetry means similar or having two halves the same shape.

[sadness]

Thank you all for the explaination. All I need now is how to work this into the questions. Sunkiss, maybe you and I can work on the lab together :) Again, thanks alot everybody.

[sunkiss]

hahahaha netime sadness!!! =) my lab midterm is next monday!!!! :( grrrrrrr :D

[sadness]

I have lab every week so I don't know when is my lab mid-term sunkiss...hihiihih. Well, g'luck on your lab-midterm.

[sunkiss]

yea me too..i have it every monday...ahhhhhh tropical storm is comin my way!!!!! no skewl for 2 days!!! hopefulli get fri too! hahahahaha i need to evacuate!!!! :D

[sadness]

Wow, lucky and unlucky you :D Be careful sunkiss :)

[sunkiss]

hihi thanx..it's no problem..im pretti used to all this stuff..hahaha at least it's still not a hurricane yet..hahahaha i just get 2 days off from skewl! muahahahaha good for me! :D