Answer:
confidence coefficient for 90% is 1.64
Step-by-step explanation:
confidence coefficient for 99% is 2.58
2.58 * 19.4/sqrt(n) = 0.04
2.598*19.4/0.04 = sqrt(n)
( 2.598*19.4/0.04)^2 = n
1587676
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confidence coefficient for 90% is 1.64
is this right?