this phenomenon occurs often to most economic variables. To illustrate the point example, consider the number of cellular phone subscribers (x) from 1989 to 199 US, together with the total gross revenue (y) of the top 100 US law firms over the We call this correlation as spurio period. Cell phone subscribers (in thousands) Year Top U.S. law firms gross revenue (in million dollar 1989 3 508.9 12 400 5 283.1 7 557.1 1990 13 500 1991 13 900 1992 11 032.8 14 300 1993 16 009.5 14 600 24 134.4 15 300 1994 16 200 33 785.7 1995 18 000 44 000.0 1996 LESSON 6.
Family of Curves
A family of curves is a group of curves that are each described by a parametrization in which one or more variables are parameters. In general, the parameters have more complexity on the assembly of the curve than an ordinary linear transformation. These families appear commonly in the solution of differential equations. When a constant of integration is added, it is normally modified algebraically until it no longer replicates a plain linear transformation. The order of a differential equation depends on how many uncertain variables appear in the corresponding curve. The order of the differential equation acquired is two if two unknown variables exist in an equation belonging to this family.
XZ Plane
In order to understand XZ plane, it's helpful to understand two-dimensional and three-dimensional spaces. To plot a point on a plane, two numbers are needed, and these two numbers in the plane can be represented as an ordered pair (a,b) where a and b are real numbers and a is the horizontal coordinate and b is the vertical coordinate. This type of plane is called two-dimensional and it contains two perpendicular axes, the horizontal axis, and the vertical axis.
Euclidean Geometry
Geometry is the branch of mathematics that deals with flat surfaces like lines, angles, points, two-dimensional figures, etc. In Euclidean geometry, one studies the geometrical shapes that rely on different theorems and axioms. This (pure mathematics) geometry was introduced by the Greek mathematician Euclid, and that is why it is called Euclidean geometry. Euclid explained this in his book named 'elements'. Euclid's method in Euclidean geometry involves handling a small group of innately captivate axioms and incorporating many of these other propositions. The elements written by Euclid are the fundamentals for the study of geometry from a modern mathematical perspective. Elements comprise Euclidean theories, postulates, axioms, construction, and mathematical proofs of propositions.
Lines and Angles
In a two-dimensional plane, a line is simply a figure that joins two points. Usually, lines are used for presenting objects that are straight in shape and have minimal depth or width.
![example, consider the number of cellular phone subscribers (x) from 1989 to 199
US, together with the total gross revenue (y) of the top 100 US law firms over the
this phenomenon occurs often to most economic variables. To illustrate the point
sa). We call this correlation as spurio
period.
Cell phone subscribers
Year
Top U.S. law firms gross
revenue (in million dolları
(in thousands)
1989
3 508.9
12 400
1990
5 283.1
13 500
1991
7 557.1
13 900
1992
11 032.8
14 300
1993
16 009.5
14 600
15 300
1994
24 134.4
16 200
1995
33 785.7
18 000
44 000.0
1996
LESSON 6.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fe371441f-8c13-4fd8-ba5f-d55c2f44a6af%2F6acecc6b-9fbb-4187-a595-d2bb3ce24654%2Fjwwftnn_processed.jpeg&w=3840&q=75)
![the other hand, it p0.t does not imply that the twa variables have
dence: It only implies that the variables have no linear dependence Figure 651 gives four atferent
1the two vartatles have no functional
narios for the correlation between two continuous varlables
Strong Positive Correlation
Strong Negative Correlation
30
10
20
S-10
10
-20
-30
4 6 8 10
2 4 6 8
10
No Dependence
and Correlation
Quadratic Dependence
and No Correlation
20
2
3 20
40
-2
-60
-4
10
2 4 6 8 10
4
8
FIGURE 6.5-1
EA](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fe371441f-8c13-4fd8-ba5f-d55c2f44a6af%2F6acecc6b-9fbb-4187-a595-d2bb3ce24654%2Flgw5m6s_processed.jpeg&w=3840&q=75)
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