Calculating odds for Totals in MLB

[nash13]

In NBA. NFL, NCAAB and NCAAF the totals are mostly -110 on avg. Is there a way to calculate the odds for MLB and NHL on avg too?

[Slick Lizard]

Are you asking what the fair price is on (example) under 7.5 when the posted total is 7 under -125?

[nash13]

not really, i just want to calculate estimations based on lines.
so under 7.5 should have what kind of avg odds?
and over 7.5 should have what kind of avg odd? etc.