Whenever FR = 0, you simply find the number with rank IR. In this case, the third number is equal to 5, so the 50th percentile is 5. You will also get the right answer if you apply the general formula:
50 t h {\displaystyle 50th} p e r c e n t i l e = ( 0.00 ) ( 9 − 5 ) + 5 = 5. {\displaystyle percentile=(0.00)(9-5)+5=5.}
