Answer:
The variance is 
Step-by-step explanation:
From the question we are told that
The sample size is n = 21
The sum of squares is 
Generally the variance is mathematically represented as

substituting values


Answer:
25x
Step-by-step explanation:
Answer:
A and D
Step-by-step explanation:
Answer:
It is the top left one
Step-by-step explanation:
Answer:
First one
Step-by-step explanation:
.20 is 20% of 100 and there is 5 boxes and 5 times 20 = 100