Please pick following TRUE OR FALSE 1. If the estimated S(t) = 0.3 at t = 36 mon
ID: 3322987 • Letter: P
Question
Please pick following TRUE OR FALSE
1. If the estimated S(t) = 0.3 at t = 36 months, this means that the 3 year survival probability is 0.3.
2. If the 3 year survival probability is 0.3, this means that 70% of patients die (‘fail’) within the first 3 years.
3. If the estimated S(t) = 0.3 at t = 36 months, this means that 30% of patients die (‘fail’) within the first 3 years.
4. Observations that are censored due to withdrawal from the study are excluded from survival analysis.
5. When comparing adverse events in two study arms, a statistically significant result is needed to make determination about safety of intervention.
6. Using intent-to-treat approach in analyzing the adverse events usually will overestimate the rates of side effects.
Explanation / Answer
Please pick following TRUE OR FALSE
1. If the estimated S(t) = 0.3 at t = 36 months, this means that the 3 year survival probability is 0.3.
Ans: TRUE
In survival analysis, S(t) denotes the subjects living for a certain amount of time after treatment.
In our case a time is 3 year. So, S(t) = 0.3, means the survival probability is 0.3.
2. If the 3 year survival probability is 0.3, this means that 70% of patients die (‘fail’) within the first 3 years.
Ans: TRUE
In our case the survival probability is 0.3 means 30% of patients are survived within the 3 years if time it means 70% patient are died within 3 years of time.
3. If the estimated S(t) = 0.3 at t = 36 months, this means that 30% of patients die (‘fail’) within the first 3 years.
Ans: FALSE
If the estimated S(t) = 0.3 at t = 36 months, this means that 70% of patients die (‘fail’) within the first 3 years. The S(t) denotes survival probability not mortality.
4. Observations that are censored due to withdrawal from the study are excluded from survival analysis.
Ans: TRUE
In survival analysis we considered only those patients who survive after a specific time means in our case we considered those patients who survived after 3 years. Because survival analysis is conducted only on survival patients except those subject who discontinued from study or dead.
5. When comparing adverse events in two study arms, a statistically significant result is needed to make determination about safety of intervention.
Ans: FALSE
For checking safety of intervention we will mention endpoints using that endpoints we will check safety. Using AE we will get idea about safety of intervention.
6. Using intent-to-treat approach in analyzing the adverse events usually will overestimate the rates of side effects.
Ans: TRUE
In ITT approach we will consider all patients those are randomized though they receive intervention or not. So, for e.g. if we conduct a study on 100 subjects and they randomized and divided in to two groups and only 70 subjects’ takes intervention, but according to ITT approach we have to consider all patients those are randomized. So, definitely using intent-to-treat approach the adverse events usually will overestimate the rates of side effects