English to Persian (Farsi) Bus/Financial Finance (general) Currencies

How'd you translate "finds a range for β_1-β_2 of 1.6 ( for Japanese yen) to 4.2" in the following?

Studies of the above type (e.g. Fama 1984) which estimate equations (12.25) and (12.26) usually find that β_1-β_2 is positive. the latter usually arises because empirically β_2 is less than zero while β_1 is usually positive. Fama (1984) finds a range for β_1-β_2 of 1.6 ( for Japanese yen) to 4.2 (for Belgian frances).