ness leading to death. The results will be compared to with those obtained from mothers of a group of healthy controls regarding the current breast-feeding status of their infants. It is expected that about 40% of controls will be bottle-fed, and we would like to detect a difference if bottle-feeding was associated with a two-fold increase of de
A case-control study is planned to investigate whether bottle-fed infants are at increased risk of death from acute respiratory infections compared breast-fed infants. The mothers of a group of cases (infants' deaths, with an underlying respiratory cause named on the death certificate) will be interviewed about the breast-feeding status of the child prior to the illness leading to death. The results will be compared to with those obtained from mothers of a group of healthy controls regarding the current breast-feeding status of their infants. It is expected that about 40% of controls will be bottle-fed, and we would like to detect a difference if bottle-feeding was associated with a two-fold increase of death (OR-2).
A. How many cases and controls need to be studied to give a 90% power of achieving 5% significance level. Copy and paste/print the answer from the software.
B. Repeat part (A) if the OR was three-fold increase. What do you notice about the
Step by step
Solved in 3 steps
