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SAP HANA Predictive Analysis Library (PAL)

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Then we get the survival estimates as follows:<br />

To compare survival estimates produced from two groups, we use log-rank test. It is a hypothesis test to<br />

compare the survival distribution of two groups (some of the observations may be censored) and is used to<br />

test the null hypothesis that there is no difference between the populations (treatment group and control<br />

group) in the probability of an event (here a death) at any time point. The methods are nonparametric in that<br />

they do not make assumptions about the distributions of survival estimates. The analysis is based on the times<br />

of events (here deaths). For each such time we calculate the observed number of deaths in each group and the<br />

number expected if there were in reality no difference between the groups. It is widely used in clinical trials to<br />

establish the efficacy of a new treatment in comparison with a control treatment when the measurement is the<br />

time to event (such as the time from initial treatment to death).<br />

Because the log-rank test is purely a test of significance, it cannot provide an estimate of the size of the<br />

difference between the groups.<br />

Implementation Step<br />

Assume that:<br />

●<br />

●<br />

●<br />

DM_<strong>PAL</strong> is a schema belonging to USER1; and<br />

USER1 has been assigned the AFLPM_CREATOR_ERASER_EXECUTE role; and<br />

USER1 has been assigned the AFL__SYS_AFL_AFL<strong>PAL</strong>_EXECUTE or<br />

AFL__SYS_AFL_AFL<strong>PAL</strong>_EXECUTE_WITH_GRANT_OPTION role.<br />

<strong>SAP</strong> <strong>HANA</strong> <strong>Predictive</strong> <strong>Analysis</strong> <strong>Library</strong> (<strong>PAL</strong>)<br />

End-to-End Scenarios P U B L I C 567

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