In baseball statistics, earned run average (ERA) is the mean of earned runs given up by a pitcher per nine innings pitched. The Earned Runs are determined by dividing the number of earned runs allowed by the number of innings pitched and multiplying by nine.
ERA is also affected somewhat by the ballpark in which a pitcher's team plays half its games, as well as the tendency of hometown official scorers to assign errors instead of base hits in plays that could be either. The First Known Use of Earned Run Average was done in the year 1947.
Example:
Calculate the ERA for the given details.
Earned Runs = 25
Innings Pitched = 5
Solution:
Apply Formula:
ERA = (Number of earned runs * 9) / (Number of innings pitched)
ERA = 45.00