To certify a lawsuit as eligible for prosecution as a class action, district court must make the following findings:
1. The number of class members renders it impracticable to join them in the action
2. The class members’ claims share common questions of law or fact
3. The claims or defenses of the proposed class representatives are typical of those for the rest of the class, and
4. The proposed class representatives will adequately protect the interests of the entire class