Answer: Minimum sample size = 110
Step-by-step explanation:
Formula to find minimum sample size :
[tex]n=(\dfrac{z\times s}{E})^2[/tex] , where z = critical z-value for confidence level, s= sample standard deviation , E = margin of error
Given: E= 4 , s= 18
Critical z-value for 98% confidence = 2.327
So, [tex]n=(\dfrac{2.327\times18}{4})^2[/tex]
[tex]=(\dfrac{41.886}{4})^2\\\\=(10.4715)^2=109.65231225\approx110[/tex]
Minimum sample size = 110
