As Both group $P$ and $Q$ have same number of students so let suppose they both contain $2$ students
Given $P_{1}+P_{2}=210$ and $Q_{1}+Q_{2}=170$
We can see that both above equations don't comment anything about their comparative value so option A and B are false.
Standard Deviation is a measure that is used to quantify the amount of variation or dispersion of a set of data values.
Group $Q$ has lesser standard deviation than group $P$ this clearly shows that $Q_{1}$ and $Q_{2}$ are more close to each other than $P1_{1}$ and $P_{2}$
Normal Distribution :- $Mean=Median=Mode$
