Suppose you plan to perform a two sample z test (or log rank test) to compare the covid 19 outcome between the vaccinated and unvaccinated groups. What is the null hypothesis for this test in terms of the IRR?Ho: IRR not equal to 0Ho: IRR equal to 0Ho: IRR not equal to 1Ho: IRR equal to 1

Table 3. Vaccine Efficacy Overall and by Subgroup in Participants without Evidence of Infection before 7 Days after Dose Z, BNT162b2 Placebo Vaccine Efficacy, % Efficacy End-Point (N-18,198) (N=18,325) 195% CI) Subgroup Surveillance Surveillance No. of Time No. of Time Cases (No. at Risk)* Cases (No. at Risk)* 162 95.0 (90.0-97.9) Overall 8 2.214 (17,411) 2.222 (17,511) Age group 1.234 (9,897) 114 1.239 (9,955) 95.6 (89.4-98.6) 16 to $5 yr 0.980 (7,500) 48 0.983 (7,543) 93.7 (80.6-98.8) w >55 yr 19 0.511 (3,880) 94.7 (66.7-99.9) 265 yr 0.508 (3.848) 0.102 (774) 5 0.106 (785) 100.0 (-13.1-100.0) 275 yr Sex 1.108 (8,762) 96.4 (88.9 99.3) Male 1.124 (8,875) 81 Female 1,090 (8,536) 81 1.114 (8,749) 93.7 (84.7-98.0) Race or ethnic group White 1.889 (14,504) 146 1.903 (14,670) 95.2 (89.8-98.1) Black or African American O 0.165 (1,502) 7 0.164 (1,486) 100.0 (31.2-100.0) All others 0.160 (1,405) 9 0.155 (1,355) 89.3 (22.6-99.8) Hispanic or Latinx 0.605 (4,764) 53 0.600 (4,746) 94.4 (82.7-98.9) Non-Hispanic, non-Latinx 1.596 (12,548) 109 1.608 (12,661) 95.4 (88.9-98.5) Country Argentina 0.351 (2,545) 35 0.346 (2,521) 97.2 (83.3-99.9) Brazil 0.119 (1,129) 0.117 (1,121) 87.7 (8.1-99.7) United States 1.732 (13,359) 119 1.747 (13,506) 94.9 (88.6-98.2) 1006 ticipants within each group at risk for the end