Need help with the Linear Algebra problem. The images are the examples.  Use a weighted Colley Method which ranks games won (loss) early in the season as 0.5 wins (losses), games won in the mid-season ranked as 1 win (loss), and games won late in the season as 2 wins (losses) to rank the following system:   During the Early Part of the Season: Team B beats C once. Team D beats E once and C once. Team E beats B once. During the Middle Part of the Season: Team A beats C once. Team D beats B once. Team E beats C once During the Later Part of the Season: Team A beats E once and C once. Team E beats B once. a. Draw a directed graph of this season. b. Write the system of equations for this season using the Massey method. c. Solve the system (using least squares) to find the ratings for each team, and use those ratings to rank them.

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
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Author:Carter
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Chapter10: Statistics
Section10.6: Summarizing Categorical Data
Problem 10CYU
Question

Need help with the Linear Algebra problem. The images are the examples. 

Use a weighted Colley Method which ranks games won (loss) early in the season as 0.5 wins (losses), games won in the mid-season ranked as 1 win (loss), and games won late in the season as 2 wins (losses) to rank the following system:

 

During the Early Part of the Season: Team B beats C once. Team D beats E once and C once. Team E beats B once.

During the Middle Part of the Season: Team A beats C once. Team D beats B once. Team E beats C once

During the Later Part of the Season: Team A beats E once and C once. Team E beats B once.

a. Draw a directed graph of this season.

b. Write the system of equations for this season using the Massey method.

c. Solve the system (using least squares) to find the ratings for each team, and use those ratings to rank them.

Example 3.1. if Team A beat Team B, Team C beat Team A, Team C beat team B, and Team
B beat Team C, using the Colley Method we would have the following system of equations:
(2+2)rA = 1 +
(2+3)rB = 1 +
(2+3)rc = 1 +
Rearranging the system gives us:
Solving this system gives us
1 1
2
1-2
Rank
2
2
3
2
2
1
4rArBrc = 1
―rA +5rB - 2rc = 0.5
-TA - 2rB+5rc = 1.5
This gives us a nice symmetric matrix system, Cr = b:
4 −1 -1
-1 5 -2
−2
-1
5
25
+rB+rc
+rA +2rc
Team
с
A
B
+rA +2rB
ΤΑ
TB
rc
0.5
ΤΑ
TB
0.42857 . We order the team rankings by the value
0.57143
rc
of the ratings with the largest rating corresponding with the top ranked team. Putting the
ratings in order from largest to smallest, we get the following ranking: Team C first, Team
A second, and Team B third.
=
1
0.5
1.5
(6)
Transcribed Image Text:Example 3.1. if Team A beat Team B, Team C beat Team A, Team C beat team B, and Team B beat Team C, using the Colley Method we would have the following system of equations: (2+2)rA = 1 + (2+3)rB = 1 + (2+3)rc = 1 + Rearranging the system gives us: Solving this system gives us 1 1 2 1-2 Rank 2 2 3 2 2 1 4rArBrc = 1 ―rA +5rB - 2rc = 0.5 -TA - 2rB+5rc = 1.5 This gives us a nice symmetric matrix system, Cr = b: 4 −1 -1 -1 5 -2 −2 -1 5 25 +rB+rc +rA +2rc Team с A B +rA +2rB ΤΑ TB rc 0.5 ΤΑ TB 0.42857 . We order the team rankings by the value 0.57143 rc of the ratings with the largest rating corresponding with the top ranked team. Putting the ratings in order from largest to smallest, we get the following ranking: Team C first, Team A second, and Team B third. = 1 0.5 1.5 (6)
3.2 Lab 3: In class portion
3.2.1 The Colley Method
As part of his mathematics PhD dissertation, Dr. Wesley Colley developed a method to rank teams
in a way that incorporates strength of schedule which can make it a little more accurate than win
percentage. At the start of the season, a team's winning percentage would 0/0 which is undefined!
The Colley Method says an untried team should have a rating of 50%, 50-50 chance the team will
win or lose. Colley also wants to have the average of all rating be roughly 0.5 as well. So we adjust
how we calculate our win percentage.
Wi
9
Regular Winning Percentage is calculated by where w is the total number of wins for
ti
Team i and t; is the total number of games placed by Team i.
Wi + 1
The Colley Winning Percentage is calculated as
Since, after each game, the denom-
ti + 2
inator increases by 1, the losers rating will decreasing and the winners rating will increase
after each game.
To set up his system, Colley sets the rating for each team, r¡, equal to its Colley win
Wi + 1
percentage. That is, r; =
In order to incorporate strength of schedule, Colley does
t₁ + 2
the following algebraic manipulation (note l, denotes the total number of losses for Team i):
(1)
(2)
(3)
0. Rearranging our equation, we now
Note we use the fact that wi
get:
(2 + ti) ri
2+2
=
Pi =
(2+ti)ri = 1+ Wi
-
Wi + 1
ti + 2
Wi Wi lj
1+ + +
2 2 2
and 1/2-1/2
½-½
(2+tį)rį = 1 +
Wi lį
2
=
(2+ti)ri = 1 +
+
24
li
(4)
Wi + li
Note that
is just the total number of games played by team i divided by 2. This is
2
where Colley made an adjustment to his system in order to incorporate strength of schedule.
Wi + lj
He does this by replacing with the sum of the ratings of the teams played by team i.
2
Thus our new Colley system has the following set up. For each Team i, we get the following
equation:
2
Wi+li
2
Wi ·lį
2
where S is the sum of the ratings of teams played by Team i.
+ S,
(5)
Transcribed Image Text:3.2 Lab 3: In class portion 3.2.1 The Colley Method As part of his mathematics PhD dissertation, Dr. Wesley Colley developed a method to rank teams in a way that incorporates strength of schedule which can make it a little more accurate than win percentage. At the start of the season, a team's winning percentage would 0/0 which is undefined! The Colley Method says an untried team should have a rating of 50%, 50-50 chance the team will win or lose. Colley also wants to have the average of all rating be roughly 0.5 as well. So we adjust how we calculate our win percentage. Wi 9 Regular Winning Percentage is calculated by where w is the total number of wins for ti Team i and t; is the total number of games placed by Team i. Wi + 1 The Colley Winning Percentage is calculated as Since, after each game, the denom- ti + 2 inator increases by 1, the losers rating will decreasing and the winners rating will increase after each game. To set up his system, Colley sets the rating for each team, r¡, equal to its Colley win Wi + 1 percentage. That is, r; = In order to incorporate strength of schedule, Colley does t₁ + 2 the following algebraic manipulation (note l, denotes the total number of losses for Team i): (1) (2) (3) 0. Rearranging our equation, we now Note we use the fact that wi get: (2 + ti) ri 2+2 = Pi = (2+ti)ri = 1+ Wi - Wi + 1 ti + 2 Wi Wi lj 1+ + + 2 2 2 and 1/2-1/2 ½-½ (2+tį)rį = 1 + Wi lį 2 = (2+ti)ri = 1 + + 24 li (4) Wi + li Note that is just the total number of games played by team i divided by 2. This is 2 where Colley made an adjustment to his system in order to incorporate strength of schedule. Wi + lj He does this by replacing with the sum of the ratings of the teams played by team i. 2 Thus our new Colley system has the following set up. For each Team i, we get the following equation: 2 Wi+li 2 Wi ·lį 2 where S is the sum of the ratings of teams played by Team i. + S, (5)
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