Select a sample of 20 individuals and the test the hypothesis =225 for IQ level. Use a=0.05
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How are you going to determine IQ level of the 20 persons? Would this relate to your inquiry?
Ho: mean = 100
Ha: mean > 100
If mean IQ = 100 and SD = 15 (as in WISC and WAIS):
Z = (score-mean)/SEm
SEm = SD/√n
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.