Suppose that Assuming that the ratio of hazard functions between the two samples is 1.5, and…

Suppose that

Assuming that the ratio of hazard functions between the two samples is 1.5, and assuming no possibility of censoring, calculate the approximate sample size, common to both groups, required to show a difference between groups at the 0.05 level of significance, with probability (power) 0.80. How does this sample size depend on hο()?