The given values are:
p = 22% = 0.22
Zc = 1.645 at 90% confidence level.
margin of error, E = 0.04
The formula we can use here is:
E = sqrt(pq/n) * Zc
0.04 = sqrt(0.22*(1-0.22)/n)*1.645
n = (0.22*(1-0.22))*(1.645/0.04)^2
n = 290.22
hence minimum sample size = 290
First step, divide 6 from both sides.
t/6=r^2+1
second step, subtract 1 from both sides
t/6 -1=r^2
Now take the square root of each side.
Done!
I wanna day, that both are correct because they substituted the same value into both expressions and the results are the same.
Both squares substitute in 6 and both equal -5.
