Question

A study is conducted to estimate the association between exposure to lead paint and ADHD in children. Out of the 400 children sampled, 63 had ADHD and 337 did not. Exposure to lead paint was found in 34 of the children who had been diagnosed with ADHD and 71 of the children who did not have a diagnosis of ADHD.

01. Create the appropriate 2x2 table:

02. Calculate and interpret the Relative Risk in this study:

03. Calculate and interpret the Odds Ratio for this study:

Answer 1

1.

	Having ADHD	Not having ADHD	Total
Exposed to led	34 (a)	71 (b)	105 (a+b)
Not exposed to led	29 (c)	337 (d)	295 (c+d)
Total	63 (a+c)	337 (b+d)	400 (a+b+c+d)

[If you dont get how I put these numbers in the right place, let me know in the comment section.]

2. Relative risk =

(Probability of desease if exposed to the risk) / (probability of desease if not exposed to the risk)

  

  

ie. There is a high positive association between risk of having ADHD and exposure to led painting.

That means expore to led paintings often leads to ADHD.

3. Odds ratio = Odds of deseased in the exposed group / Odds of desease in the unexposed group

  

  

ie, risk of getting ADHD is almost 4 times higher when exposed to led paintings than when not exposed.

If any doubts, let me know in the comment section. thank you