The World Series of baseball in the United States is a best-of-seven series. Therefore, the first team to win four games is the victor. To try to make the series fair, the first two games are played at one team's home park, the next three games are played at the other team's park (just two may be played if one team wins four in a row), and the final two games (if needed) are scheduled at the first team's park. It is therefore possible that one team will play four games in its home park while the other team may only play three games at home.
It is generally assumed that there is some advantage to playing at home. Each baseball park is different, so there may be some advantage to playing on a familiar field. The hometown fans provide emotional support for the team, and so on. Is there an advantage to playing World Series games on your home field?
The dataset contains information on the year, the two teams competing in the world series, whether the American League (AL) or National League (NL) team won the game, and the AL and NL winning at home or away percentage.
For all the games given, the teams won at home 55.5% of the time and away games were won 45% of the time. Using these probabilities and assuming that the chance of winning a home game is constant and that the games are independent, one can find the probabilities of winning in exactly 4, 5, 6 or 7 games as well as some other basic probability questions.
The 2-way ANOVA by League and Home/Away shows significance for both factors. While the interaction term is not significant at the .05 level, the interaction plot suggests that the home field advantage may be greater for American league teams than for National League teams.