Answer: Tt is unlikely to have change in the sample mean score is less than 10 points .
Step-by-step explanation:
Given : Mean : 
Standard deviation : 
Sample size : n= 100
We assume that the change in students scores are normally distributed.
Let X be the random variable that represents the change in students scores .
Z score : 
For x = 10

By using the standard normal distribution table , the probability that the change in the sample mean score is less than 10 points :-

Since the calculated probability is less than 0.5.
So , we say that it is unlikely to have change in the sample mean score is less than 10 points .