Daycare centers expose children to a wider variety of germs than if they stayed at home. This has the obvious downside of frequent colds, but it also serves to challenge the immune system of children at a critical stage in their development. A study by Gilham et al. (2005) researched whether the exposure of children to a daycare environment and other regular social activities away from home affected their probability of later developing acute lymphoblastic leukemia (or ALL) with the following results: Children with ALL Children without ALL Total
Daycare 1020 5343 6363
No daycare 252 895 1147
Total 1272 6238 7510
A) Perform a χ2 contingency table analysis to answer whether the probability of developing ALL is associated with having been in a daycare environment.
B) Calculate the odds ratio for describing this dataset (report the OR that is greater than 1) and provide its interpretation (similar to in-class statements regarding the frogs).
C) What is the relative risk of getting ALL for children who attend daycare?