Q5. In 1992, the U.S. Public Health Service and the Centers for Disease Control
ID: 3306042 • Letter: Q
Question
Q5. 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 pExplanation / Answer
Given table data is as below
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calculation formula for E table matrix
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expected frequecies calculated by applying E - table matrix formulae
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calculate chisquare test statistic using given observed frequencies, calculated expected frequencies from above
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set up null vs alternative as
null, Ho: no relation b/w X and Y OR X and Y are independent
alternative, H1: exists a relation b/w X and Y OR X and Y are dependent
level of significance, = 0.05
from standard normal table, chi square value at right tailed, ^2 /2 =3.8415
since our test is right tailed,reject Ho when ^2 o > 3.8415
we use test statistic ^2 o = (Oi-Ei)^2/Ei
from the table , ^2 o = 8.012
critical value
the value of |^2 | at los 0.05 with d.f (r-1)(c-1)= ( 2 -1 ) * ( 2 - 1 ) = 1 * 1 = 1 is 3.8415
we got | ^2| =8.012 & | ^2 | =3.8415
make decision
hence value of | ^2 o | > | ^2 | and here we reject Ho
^2 p_value =0.0046
ANSWERS
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null, Ho: no relation b/w X and Y OR X and Y are independent
alternative, H1: exists a relation b/w X and Y OR X and Y are dependent
test statistic: 8.012
critical value: 3.8415
p-value:0.0046
decision: reject Ho
we don't support that the preconception use of folic acid and race are independent.
col1 col2 260 299 559 15 41 56 275 340 N = 615Related Questions
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