Question 1197459
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Hi  
 95% confident  ⇒  z = 1.96
σ = 300,   ME = 25
How large of a sample size is required?
{{{ME = z*sigma/sqrt(n)}}}
0r
n = {{{( z*sigma/ME)^2}}}
n = {{{((1.96*300)/25)^2 ))}}} = 553.1904  0r sample Size =554 (always round Up)

 = CI	z = value
90%	z =1.645    
92%	z = 1.751
95%	z = 1.96   Invnorm(.975)  2-sided (.95 + .05/2 = .975 )
98%	z = 2.326  
99%	z = 2.576
Wish You the Best in your Studies.
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