Question:
IQ scores from the general population form a normal distribution with a m = 100 and s = 15. However, data indicate that children's intelligence may be affected if their mothers have German measles during pregnancy.
Using hospital records, a researcher obtained a sample of n = 25 school children whose mothers all had German measles during their pregnancies. The average IQ for this sample was x? = 94.
Do these data indicate that German measles have a significant effect on IQ? Test with alpha=.05.