In: Math
Level of Significance , α =
0.05
std dev = σ = 0.100
power = 1-ß = 0.8
ß= 0.2
δ= 0.01
Z ( α ) = 1.6449 [excel
function: =normsinv(α)
Z (ß) = 0.8416 [excel
function: =normsinv(ß)
sample size needed = n = ( ( Z(ß)+Z(α) )*σ / δ )² = (
( 0.8416 + 1.6449 )
* 0.1 / 0.01 ) ²
= 618.2557
so, sample size =
619