The income elasticity of demand for dental services is 2.40, and the income elasticity of demand for nursing homes is 0.90. based on these estimates, dental services are a(n) and nursing home care is a(n)

luxury good, normal good    

Explanation:

          Income elasticity of demand, in economics, is the measure of the responsiveness of a quantity demanded as a service or goods to the change with income.

          It is the relationship between the change in a quantity demanded and the change in the income.

          For luxury goods and services, income elasticity of demand rises more than the rise in  real income. It have an income elasticity of demand of greater that  +1.

         For normal goods, the quantity demanded increases when the income is increased. The income elasticity of demand is positive. The income elasticity for demand lies in the range of 0 and +1.

          Hence, since the income elasticity for demand for dental services is 2.40, it is luxury goods and for nursing home care is 0.90, it is a normal good or service.

Therefore the answer is ---

luxury good, normal good  

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

c it has to be i googled it