We have, the marks of 10 passed students are 9,6,7,8,8,9,6,5,4 and 7.
In ascending order , 4,5,6,6,7,7,8,8,9,9.
And appeared students = 15
So, number 15 is odd then median is the value of
()th means
8th observations.
but we don’t have the marks of 5 failed students which are obviously marks less than 4.
So including the unknown 5 observations ,
8th observations is 6.