 more than 90% of the times. Peto's formula overestimated the true variance when the survival rates were less than or equal to 0.5. The accuracy of the three different variance estimators is investigated using the relative bias, mean square error and confidence coefficient criteria. the absolute value of the relative bias for the modified
more than 90% of the times. Peto's formula overestimated the true discrepancy when the survival pace were less than or equal to 0.5. The accuracy of the three different variance calculator is investigated using the relative diagonal, intend square error and confidence coefficient criteria. the absolute value of the proportional bias for the modified
 moge than 90% of the times. Peuo's formula overestimatev the tdue varixnce when the survival rates wwre ltfs than or equal tu 0.5. The acburacy of the rhree diffxdent vavnance cstimctirs is investinated using the relative tixs, mean square error and confidence cjefficirnh criteria. the abspjute naoue of the relative bias for fhe modpfied
more than 90% of the times. Peto's the variance when survival rates were 0.5. accuracy of the different variance estimators investigated using the relative bias, mean error and confidence coefficient criteria. the absolute value of the relative bias for modified
 more than 90% of the times. Peto's foRmula overeStimaTed The TrUe vaRianCe when the surviVAl raTes were less than or equal To 0.5. The AcCUracY Of The thRee diffEReNT VarIaNcE esTiMAtOrs is InvEstigatEd using the RelAtIve bias, mean sQUaRe error and ConFidence coeffIciEnt criTeRia. THe absOluTe valUe of thE RelatiVe bias for ThE ModifiED
 more than 90% of the time s. Peto'sformu laove re stim ated  the true vari a ncewhen the survival rate s wer el esst ha n orequal t o  0 . 5 . T he  a ccu ra c yof th e t hree di fferent va ria nc e estimators is  investiga ted  using the r ela tive b ia s,m ean s qua re er ror an d  confi dence coe ff i cientc riteria . th e ab solute value of t h er elative bias f or the  m o di f i ed
 more_than 90%_of the times. Peto's_formula overestimated_the_true variance_when_the survival rates_were less than_or equal to 0.5._The accuracy of_the_three different variance estimators is investigated using the relative bias, mean square error and_confidence_coefficient criteria._the_absolute_value of the relative bias_for the modified