Answer:
Since the frequency of the numbers vary, the students are not effective at generating random numbers.
Step-by-step explanation:
If they were effective, all the numbers should have around the same probability of being generated.
Between 1 and 20 there are 20 numbers, so the frequency of each number should be around 100%/20 = 5%.
Since the frequency of the numbers vary, the students are not effective at generating random numbers.