In 1992, the U.S. Public Health Service and the Centers for Disease Control and Prevention recommended that all women of childbearing age consume 400mg of folic acid
daily to reduce the risk of having a pregnancy that is affected by a neural tube defect such as spina bifida or anencephaly. In a study, 615 pregnant women were called by a teratology information service about their use of folic acid supplementation. Out of 559 White women, 260 reported of using folic acid before conception. Among 56 Black women, only 15 reported of using folic acid before conception. The researchers wished to determine if preconception use of folic acid and race are independent.
a. Choose appropriate statistical test to determine if the use of folic acid and race are independent and test significance of your result at p<0.05?
(2 points for drawing contingency table and 4 points for calculations and explanation)