Using the following table of data from a cross-sectional study, complete the odds ratios, calculate the expected joint effects for the additive and multiplicative model, indicate if there is interaction, and indicate the direction of this interaction using the observed and expected joint effects model of interaction. Use the “calculations” section to show your work.

Exposure to Z	Exposure to A	Cases	Controls	Odds ratio
Absent	Absent	6,483	12,102	1.0
	Present	5,228	3,291
Present	Absent	357	222
	Present	252	53

Calculations:

Calculate the expected joint effect for the additive model:

Calculate the expected joint effect for the multiplicative model:

For both the additive and multiplicative scales, indicate if there is interaction and define the direction of this interaction if it is present.