Answer and step-by-step explanation:
Yes, it does have practical significance.
If the method was ineffective, the chance of an increase this large was 3/10, or 30%. This means with an ineffective teaching method, there was a 100-30 = 70% chance of not seeing a score increase this large.
Since we did see a result this large, and 30% is not a very large chance, we can say that the method was most likely effective.