I cannot choose between the answers of (b) and (e).

This is because for (e), the observed median survival time for the Hard difficulty can be higher as the confidence goes into the negatives. (b) also makes sense.

I don't think that (d) is correct as we can never be "certain" of anything as this is only from a 95% confidence interval.

Data Hard Easy ooo 8 40 50 30 70 80 10 20 Re-Sample Hard Easy 40 70 80 90 10 20 30 Bootstrap Distribution 40 -30 10 7.8 Which one of the following statements about the bootstrap confidence interval is true? It is a fairly safe bet that the underlying median survival time for the Easy difficulty level is somewhere between 1.6 minutes higher and 18.5 minutes lower than the underlying median survival time for the Hard difficulty level. The observed difference in median survival times is 7.8 minutes and it is believable that the underlying difference in median survival times is up to 10.7 minutes higher or 9.4 minutes lower than the point estimate. It is not believable that the underlying median survival time for the Easy difficulty level is the same as the underlying median survival time for the Hard difficulty level. We know for certain that the difference in underlying median survival times between the two difficulty levels is between-1.6 and 18.5 minutes. It is believable that the observed median survival time for the Hard difficulty level is higher than the observed median survival time for the Easy difficulty level. Data Hard Easy ooo 8 40 50 30 70 80 10 20 Re-Sample Hard Easy 40 70 80 90 10 20 30 Bootstrap Distribution 40 -30 10 7.8 Which one of the following statements about the bootstrap confidence interval is true? It is a fairly safe bet that the underlying median survival time for the Easy difficulty level is somewhere between 1.6 minutes higher and 18.5 minutes lower than the underlying median survival time for the Hard difficulty level. The observed difference in median survival times is 7.8 minutes and it is believable that the underlying difference in median survival times is up to 10.7 minutes higher or 9.4 minutes lower than the point estimate. It is not believable that the underlying median survival time for the Easy difficulty level is the same as the underlying median survival time for the Hard difficulty level. We know for certain that the difference in underlying median survival times between the two difficulty levels is between-1.6 and 18.5 minutes. It is believable that the observed median survival time for the Hard difficulty level is higher than the observed median survival time for the Easy difficulty level