Pre-computes running average runs per delivery for each league, organized
by match date. This allows efficient lookup of "league average as of date X"
without data leakage.
Usage
build_league_running_averages(conn, format, gender)
Arguments
- conn
DBI connection to the database.
- format
Character. Match format: "t20", "odi", or "test".
- gender
Character. Gender: "male" or "female".
Value
Data frame with columns: event_name, match_date, cumulative_runs,
cumulative_deliveries, running_avg_runs.
