TY  - GEN
AU  - Lan,K K
AU  - DeMets,D L
TI  - Changing frequency of interim analysis in sequential monitoring
SN  - 0006-341X
PY  - 1989///1113
KW  - Biometry
KW  - Clinical Trials as Topic
KW  - methods
KW  - Humans
KW  - Models, Statistical
KW  - Probability
N1  - Publication Type: Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S
ER  -