To see if breast-feeding influences the incidence of the disease rickets, researchers study rates of breast-feeding of infants with and without rickets. This is an example of
A. experimental research.
B. observational research.
C. epidemiological research.
D. double-blind placebo-controlled research.
Question 2
It is very important in a double-blind, placebo-controlled study that all of the factors that could influence the study results are
A. completely different for the groups of subjects.
B. equal and opposite for the groups of subjects.
C. kept to a minimum.
D. kept the same for the groups of subjects.
Population predictions for 2000–2050, using three different total fertility rates (
Stellar Birth Rates
Results from sequential study of two cohorts tested at three ages and at three different points in t
Rates of Car Injuries and Fatalities by Age
Leonardo da Vinci, Study for a Sleeve.
Partial map of disease genes on human chromosome 21