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DTSTART:20231002T030000
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BEGIN:VEVENT
DESCRIPTION:Presenter:\nLudwig A. Hothorn (Leibniz University Hannover\, Ge
rmany)\nChair:\nDr. Bernd-Wolfgang Igl (Bayer AG)\n\nAbstract:\nDose-respo
nse analysis is a central part in statistical evaluation of toxicological
bioassays. Two approaches are used: simultaneous testing of order-restrict
ed multiple contrasts and regression-based modeling. The first one conside
rs the DOSE qualitatively\, i.e. as randomized factor whereas the second a
ssumes DOSE as quantitative covariate (in bioassays commonly for grouped d
ose levels). Both approaches are demonstrated by means of real data exampl
es where robustness\, e.g. against downturn effects is discussed. Moreover
\, a new approach is explained\, where DOSE is jointly considered both qua
li- and quantitatively.\nThe recent p-value controversy is discussed from
the perspective of regulatory toxicology where first confidence intervals
for specific selected effect sizes are recommended. Secondly\, the inclusi
on of individual data points within or without a prediction interval is pr
oposed as an alternative to common-used null-hypothesis significance tests
. The prediction intervals are defined for any single future value of a gr
oup with sample size n_i using the controls of multiple historical bioassa
ys. The within- and between assay variance is considered by a mixed effect
model.\nFinally\, the question will be discussed why the proof of safety
(&bdquo\;be safe in negative results&ldquo\;) is not widely used in routin
e up to now.\nThe &ldquo\;third main set&rdquo\; of statistics is: softwar
e must be available. And therefore all methods are demonstrated using //R-
//CRAN packages.\n\nRegistration: \;\nThis webinar will take place fro
m 14:00 - 15:00 and is free to attend. \n\nRegistration has now closed.
DTEND:20180619T130000Z
DTSTAMP:20240624T073316Z
DTSTART:20180619T120000Z
LOCATION:
SEQUENCE:0
SUMMARY:PSI Toxicology SIG Webinar
UID:RFCALITEM638548111966218639
X-ALT-DESC;FMTTYPE=text/html:### Presenter:

\nLudwig A. Hothorn *(Le
ibniz University Hannover\, Germany)*\n### Chair:

\nDr. Bernd-W
olfgang Igl *(Bayer AG)*

\n

\n**Abs
tract:**

\nDose-response analysis is a central part in stati
stical evaluation of toxicological bioassays. Two approaches are used: sim
ultaneous testing of order-restricted multiple contrasts and regression-ba
sed modeling. The first one considers the DOSE qualitatively\, i.e. as ran
domized factor whereas the second assumes DOSE as quantitative covariate (
in bioassays commonly for grouped dose levels). Both approaches are demons
trated by means of real data examples where robustness\, e.g. against down
turn effects is discussed. Moreover\, a new approach is explained\, where
DOSE is jointly considered both quali- and quantitatively.

\nThe rec
ent p-value controversy is discussed from the perspective of regulatory to
xicology where first confidence intervals for specific selected effect siz
es are recommended. Secondly\, the inclusion of individual data points wit
hin or without a prediction interval is proposed as an alternative to comm
on-used null-hypothesis significance tests. The prediction intervals are d
efined for any single future value of a group with sample size n_i using t
he controls of multiple historical bioassays. The within- and between assa
y variance is considered by a mixed effect model.

\nFinally\, the qu
estion will be discussed why the proof of safety (&bdquo\;be safe in negat
ive results&ldquo\;) is not widely used in routine up to now.

\nThe
&ldquo\;third main set&rdquo\; of statistics is: software must be availabl
e. And therefore all methods are demonstrated using //R-//CRAN packages.\n

### \nRegistration: \;

\nThis webinar will take place from 14:
00 - 15:00 and is free to attend.

\n

\nRegistration has now clo
sed.
END:VEVENT
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