Pitchers ERA in MLB?

Question

In MLB, how do they determine a Pitcher's Earned Run Average? (ERA)

Answer 1

above are correct, but WHIP is more important. (Walks, Hits, Divided by Innings pitched) A little better indicator of how a pitcher is doing.

Answer 2

Earned Runs TIMES Nine DIVIDED by Innings Pitched.

Example: (15 * 9) / 40.67 = 3.319400

Or to get a more accurate number:

Earned Runs TIMES Twenty Seven DIVIDED by Number of Outs Recorded.

Example: (15 * 27) / 122 = 3.31967

Answer 3

Even in lower levels of baseball, the ERA is the total amount of earned runs divided by total innings pitched.