Comparison of the strengths of Japanese Collegiate Baseball Leagues in past 30 seasons Takashi Toriumi 1, Hirohito Watada 2, The Tokyo Big 6 Baseball

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1 Powered by TCPDF ( Title 東京六大学野球リーグ及び東都大学野球リーグを含めた各大学野球連盟における過去 30シーズンの平均競技力の比較研究 Sub Title Comparison of the strengths of Japanese collegiate baseball leagues in past 30 seasons Author 鳥海, 崇 (Toriumi, Takashi) 綿田, 博人 (Watada, Hirohito) Publisher 慶應義塾大学体育研究所 Publication year 2018 Jtitle 体育研究所紀要 (Bulletin of the institute of physical education, Keio university). Vol.57, No.1 ( ),p Abstract The Tokyo Big 6 Baseball League (BIG6) and the Tohto University Baseball League (TOHTO) are the top two collegiate baseball leagues in Japan. Both leagues consists of six teams and are highly competitive ; however, there is no opportunity for the teams in the two leagues to compete directly against each other except for the national championships. In this report, we calculate the strengths of six teams across both leagues and compare the superiority of them. Using the Bradley-Terry model and Markov model, we estimate the strengths of each team in both leagues. The Kendall tau rank correlation coefficient of both methods was as high as The results indicate that the first team in TOHTO had the highest strength calculated by Bradly-Terry model on the other hand the first team in BIG6 had the highest by Markov model. On comparing the strengths of the same rankings in both leagues, the strengths of every team in TOHTO are higher than those of the corresponding teams in BIG6 in both methods. This is because BIG6 consists of only the same six teams, while TOHTO consists of 21 teams, with the sixth-ranked team playing a replacement game against the first team of the second division every season. Notes 研究資料 Genre Departmental Bulletin Paper URL

2 Comparison of the strengths of Japanese Collegiate Baseball Leagues in past 30 seasons Takashi Toriumi 1, Hirohito Watada 2, The Tokyo Big 6 Baseball League (BIG6)and the Tohto University Baseball League (TOHTO)are the top two collegiate baseball leagues in Japan. Both leagues consists of six teams and are highly competitive; however, there is no opportunity for the teams in the two leagues to compete directly against each other except for the national championships. In this report, we calculate the strengths of six teams across both leagues and compare the superiority of them. Using the Bradley- Terry model and Markov model, we estimate the strengths of each team in both leagues. The Kendall tau rank correlation coefficient of both methods was as high as The results indicate that the first team in TOHTO had the highest strength calculated by Bradly-Terry model on the other hand the first team in BIG6 had the highest by Markov model. On comparing the strengths of the same rankings in both leagues, the strengths of every team in TOHTO are higher than those of the corresponding teams in BIG6 in both methods. This is because BIG6 consists of only the same six teams, while TOHTO consists of 21 teams, with the sixth-ranked team playing a replacement game against the first team of the second division every season. Ⅰ

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6 PPPP(XX nn = jj) = pp rrrr PPPP(XX nn 1 = rr) = p ij r r j 1 r r n n rr SS rr jj = rr ii pp iiii ii SS rs r (nn) pp rrrr PPPP(XX0 = rr) rr SS 1 6 m 6 r i r1s r2 r2 1 r2 3 r2 r2 S r3 r3 r3 4 rs r r r r

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A comparative study of the team strengths calculated by mathematical and statistical methods and points and winning rate of the Tokyo Big6 Baseball Le

Powered by TCPDF (www.tcpdf.org) Title 東京六大学野球リーグ戦において勝敗結果から計算する優勝チームと勝点勝率との比較研究 Sub Title A comparative study of the team strengths calculated by mathematical and statistical methods and points and winning