Question

Use the following information to complete the questions below

Hypothesis: Women exposed to lead paint in childhood (exposure) are at higher risk of having a child with low birth weight (disease outcome).

	Disease +	Disease -	Total
Exposure +	128	324	452
Exposure -	310	760	1070

Calculate the odds of exposure (early lead paint exposure) among women who had a child with low birth weight. Enter your answer with 3 decimal places below.

Calculate the odds of exposure (early lead paint exposure) among women who had a child who was not low birth weight. Enter your answer with 3 decimal places below.

Calculate the odds ratio (OR) of having a low birth weight child comparing women with lead paint exposure in childhood to women without lead paint exposure. Enter your answer with 2 decimal places below.

Does it appear to you that women who have early exposure to lead paint are more likely to have a low birth weight children compared to women not exposed to lead paint? Explain your answer in 1-2 sentences.

Answer 1

P(Exposure among women who had a child with low birth weight) = 128/(128+310) = 128/438

P(No exposure among women who had a child with low birth weight) =310/(128+310) = 310/438

Odds of Exposure (early lead paint exposure) among women who had a child with low birth weight = (128/438)/(310/438)

Odds of Exposure (early lead paint exposure) among women who had a child with low birth weight = 128/310

Odds of Exposure (early lead paint exposure) among women who had a child with low birth weight = 0.413

P(Exposure among women who had a child was not low birth weight) = 324/(324+760) = 324/1084

P(No exposure among women who had a child was not low birth weight) =760/(324+760) = 760/1084

Odds of Exposure (early lead paint exposure) among women who had a child was not low birth weight = (324/1084)/(760/1084)

Odds of Exposure (early lead paint exposure) among women who had a child with low birth weight = 324/760

Odds of Exposure (early lead paint exposure) among women who had a child with low birth weight = 0.426

Odds ratio (OR) of having a low birth weight child comparing women with lead paint exposure in childhood to women without lead paint exposure = [Odds of Exposure (early lead paint exposure) among women who had a child with low birth weight/Odds of Exposure (early lead paint exposure) among women who had a child with low birth weight]

Odds ratio (OR) of having a low birth weight child comparing women with lead paint exposure in childhood to women without lead paint exposure = (128/310)/(324/760) = (128*760)/(310*324)

Odds ratio (OR) of having a low birth weight child comparing women with lead paint exposure in childhood to women without lead paint exposure = 0.969

Interpretation of Odd Raito:

As the value of odds ratio is less than 1, it cannot be concluded that women who have early exposure to lead paint are more likely to have a low birth weight children compared to women not exposed to lead paint.