Has anyone compiled standard deviations among team run differentials for MLB seasons?

To be clear, let's say there are 8 teams in the league. For each team, take runs scored minus runs allowed. This is the variable that I would like to see the league standard deviation for.

I think I read that people have looked at it as a sign of league quality, so I was hoping it has been done. If not, someone might like to take it as a project. Doesn't seem too extensive.

Also, I saw a stat on BBRef: defensive efficiency. Is that just 1-BABIP?

To be clear, let's say there are 8 teams in the league. For each team, take runs scored minus runs allowed. This is the variable that I would like to see the league standard deviation for.

I think I read that people have looked at it as a sign of league quality, so I was hoping it has been done. If not, someone might like to take it as a project. Doesn't seem too extensive.

Also, I saw a stat on BBRef: defensive efficiency. Is that just 1-BABIP?

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