Nope. Just because two things occur together, it does not mean there is a cause and effect relationship between them.
Are there any other stats on student learning for these states? Looking at ACT/SAT scores is a limited scope. And besides, which states are # 45 and 46 on that list? If you only listed the states without unions, then #45 and 46 *do* have unions — and they are near the bottom of the list.
Only five states do not have collective bargaining for educators and have deemed it illegal.
Those states and their ACT/SAT rankings are as follows:
South Carolina – 50th
North Carolina – 49th
Georgia – 48th
Texas – 47th
Virginia – 44th
If you are wondering, Wisconsin, with its collective bargaining for teachers, is ranked 2nd in the country.