Total Par (3,4,5) Avg Score is a statistic that shows the average score for holes with a particular par (indicated by the title).
This statistic is best used in conjunction with the other stats like it for different pars (Total Par 3 Avg Score, Total Par 4 Avg Score and Total Par 5 Avg Score) to see the relative performance of a player on different par holes - keep in mind that Par 4 holes will have a higher score than Par 3 Holes and likewise Par 5 holes will have a higher score than Par 4 holes).
This stat is calculated by adding up the total score of every hole with the correct par and dividing it by the number of holes of that par in the included rounds - (total score of par 3 holes รท number of par 3 holes).
Total Par (3,4,5) Avg Score can be found on the Summary Report.