SOLUTION: he standard iq test has a mean of 96 and a standard deviation of 14. We want to be 90% certain that we are within 4 IQ points of the true mean. Determine the required sample size

Question 1143470: he standard iq test has a mean of 96 and a standard deviation of 14. We want to be 90% certain that we are within 4 IQ points of the true mean. Determine the required sample size.
a, 1
b. 6
c. 34
d. 130
Answer by amarjeeth123(570) (Show Source): You can put this solution on YOUR website!
We have,
z=1.64 for a confidence interval of 90%
sigma=14
CI=4
CI=z*sigma/sqrt(n)
Plugging in the values we get,
4=1.64*14/sqrt(n)
sqrt(n)=(1.64*14/4)=5.74
n=32.9 which is approximately 34.
Answer=(c)34

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