The explanation obtained, by the statistical analysis,
shows some significant and insignificant behaviors.
• Indeed, taking into account a certain type of
activities (clothes, shoes, etc), the flow of clients
depends strongly on some other variable. There is a
linear dependence on the surface of the business
activity. Moreover there is a linear dependence on
the inverse of the square of the distance from the
main street.
• On the contrary, taking into account a completely
different type of activities (food), the flow of clients
is quite independent on some other variable. There is
a linear dependence on the sinus of both the surface
of the business activity and its distance from the
main street.
This kind of explanation has been considered reasonable
and satisfactory, because the first class of business
activities are expected to be sensitive to the other
variables, whilst the second class seems to be quite
insensitive.
4. A TWO WAY VARIANCE ANALYSIS
The last part of the spatial analysis has been only a
simulation. Indeed although space - time depending data
analysis is very important, to understand the behavior of
many phenomena and processes, referred to the space
and rapidly changing in the time, data acquisition is often
really very, very expensive.
Therefore an old database, subdivided into regions and
epochs, has been acquired and it has formed the set of
data, collected together into two - dimensional cells. The
information into the cells is represented by a statistical
mono - dimensional variable whose elements are the
values of the attributes of the information itself.
A more sophisticated investigation could be done, by
using a three - way variance analysis, to better exploit the
spatial variability. Furthermore a statistical multi -
dimensional variable increases by the repetitions, as
much as possible, the degrees of freedom. Finally the
interactions among the cells themselves can be also taken
into account.
In the present work, a two - way variance analysis
without repetitions has been done. The different areas of
the city represent the blocks and the different epochs of
collected data are the treatments.
*** Two-way Variance of Analysis ***
Legend: VI = Blocks
V2 = Treatments
VI
V2
Residuals
A
23768.17
2365.42
20038.42
B
107
5
535
C
222.13
473.08
37.45
D
5.93
12.63
F
3.06
1.42
Note: The estimated effects are balanced.
The principal aim of the variance analysis is to maximize
the layer - variance, describing the phenomena according
to some selected the layer: rows, columns (piles) models,
respect to the residual variance which, on the contrary,
represents the random variability of the data.
The two - way variance analysis shows that the estimated
effects are balanced. This means that both the spatial
variability and the time variability are significantly
greater than the random errors. The simulation appears
reasonable and satisfactory, fully confirming the studies
performed analyzing real data.
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Department Geodätische Wissenschaften Zürich 1997.
Carosio A.: Fehlertheorie und Ausgleichung rechnung.
ETH Zürich Department Geodätische Wissenschaften
Zürich 1998.
Everitt BrianS.: Statistical Analysis using S-Plus.
Chapman&Hall 1996.
Flury B., Riedwyl H.: Angewandte multivariate Statistik.
Gustav Fischer Verlag 1983.
Morrison D.F.: Multivariate Statistical Methods. Mc
Graw Hill 1989.
A = Sums of the Squares
B = Degrees of Freedom
C = Variances
D = F of Fisher (expected values)
E = F (alpha = 1%, on two sides)