In the state of Connecticut, what is the name of the instution with the highest percent rank for freshman retention percentage within the sector?
name of the institution refers to chronname;  highest percent rank for freshman retention percentage within the sector refers to MAX(retain_percentile);
SELECT chronname FROM institution_details WHERE state = 'Connecticut' AND retain_percentile = ( SELECT MAX(retain_percentile) FROM institution_details WHERE state = 'Connecticut' )