Answer:
The margin of error (E) 
Step-by-step explanation:
Given,
mean 
standard deviation 
sample size 

Critical value


Critical value 


The margin of error (E) 


Hence, The margin of error (E) 
Complete question is attached in below.
<span>When 20 is increased by 30% of itself
</span><span>When 20 is added to by (30% OF 20)
</span><span>
20 + (30% x 20)
</span><span>20 + (0.3 x 20)
</span><span>
20 + (6)
</span>26