Description Usage Arguments Details Value Note Author(s) References See Also Examples
The function Haybittle
is used in calls to the functions
GrpSeqBnds
and PwrGSD
as a possible setting for the
argument EfficacyBoundary
. NOTE: the Haybittle method is not
used for construction a futility boundary (does this even make
sense?). The Haybittle method is one of four currently availiable
choices, the others being LanDemets
, SC
(stochastic
curtailment), and user specified.
1 |
alpha |
The total probability of type I error. |
b.Haybittle |
User specified efficacy boundary at all but the last analysis. |
from |
WARNING EXPERIMENTAL: See the documentation under
|
to |
See above. |
The Haybittle method is the simplest of all methods for efficacy boundary construction. You just specify a value such as 3 which is so large that multiple testing with standard normal criterion 3 (upper quantile is 0.00135) means that after 20 analyses you've spent only 0.027. The value of the criterion for the final analysis is determined so that the total type I error is obtained.
An object of class boundary.construction.method
which is really a list
with the following components. The print method displays the original
call.
type |
Gives the boundary construction method type, which is the character string "Haybittle" |
alpha |
The numeric value passed to the argument 'alpha' which is the total probability of type I error. |
b.Haybittle |
The numeric value passed to the argument 'b.Haybittle' which is the user specified efficacy boundary at all but the last analysis. |
from |
Description of 'comp2' |
to |
You're not using this, right? |
call |
see above. |
The print method returns the call by default
Grant Izmirlian
see references under PwrGSD
LanDemets
, SC
, GrpSeqBnds
, and PwrGSD
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | ## example 1: what is the result of calling a Boundary Construction Method function
## A call to 'Haybittle' just returns the call
Haybittle(alpha=0.05, b.Haybittle=3)
## It does arguement checking...this results in an error
## Not run:
Haybittle(alpha=0.05)
## End(Not run)
## but really its value is a list with the a component containing
## the boundary method type, "LanDemts", and components for each
## of the arguments.
names(Haybittle(alpha=0.05, b.Haybittle=3))
Haybittle(alpha=0.05, b.Haybittle=3)$type
Haybittle(alpha=0.05, b.Haybittle=3)$alpha
Haybittle(alpha=0.05, b.Haybittle=3)$b.Haybittle
Haybittle(alpha=0.05, b.Haybittle=3)$call
## example 2: ...But the intended purpose of the spending functions its
## intended purpose is in constructing calls to 'GrpSeqBnds' and to 'PwrGSD':
frac <- c(0.07614902,0.1135391,0.168252,0.2336901,0.3186155,
0.4164776,0.5352199,0.670739,0.8246061,1)
test <- GrpSeqBnds(frac=frac, EfficacyBoundary=Haybittle(alpha=0.025, b.Haybittle=3))
|
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