An IQ test is designed so that the mean is 100 and the standard deviation is 20
ID: 3071019 • Letter: A
Question
An IQ test is designed so that the mean is 100 and the standard deviation is 20 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 90% confidence that the sample mean is with 4 IQ points of the true mean. Assume that population standard deviation =20 and determine the required sample size using technology. Then determine if this is a reasonable sample size for a real world calculation.
The required sample size is ______ (round up to the nearest integer)
Would it be reasonable to sample this number of students?
No, this number of IQ scores is a fairly large number
Yes, this number of IQ test scores is a fairly small number.
No, this number of IQ test scores is a fairly small number.
Yes, this number of IQ test scores is a fairly large number
Explanation / Answer
Yes, this number of IQ test scores is a fairly small number
for 90 % CI value of z= 1.645 standard deviation = 20.00 margin of error E = 4 required sample size n=(z/E)2 = 68.0