My Exercise

From Humphrey, I determined the following pace conversions:

2.5 miles2 miles1 mile
9:008:528:22
8:007:537:26
7:006:536:30

A good fit for these points is that a runner's total time at distance D is given by a*D-b, which is equivalent to saying the pace is a-b/D. This suggests the 1.5 mile times are 13:03, 11:36, and 10:11, respectively.

Using linear interpolation, we can convert from Texas' 1.5 mile times for 25-29 year-old males PRT Standards to 2.5 mile times, giving us rough 2.5 mile time percentages:

%1.5 Mile TimeEst 2.5 Mile Time
50%12:1621:10
60%11:4220:10
70%11:1719:26
80%10:4318:26
90%10:0417:18
Humphrey, L. Pace Calculator. https://lukehumphreyrunning.com/hmmcalculator/race_equivalency_calculator.php Age Gender PRT Standards. https://www.dps.texas.gov/ETR/docs/ageGenderPRTStndrdsB.pdf