On arranging the data in ascending order, we get

M = Size of(N+1/2) th item = Size of (29+1/2) th item = Size of 15 th item

and 15th item lies in cf 21, hence M = 156

On arranging the data in ascending order, we get

M = Size of(N+1/2) th item = Size of (29+1/2) th item = Size of 15 th item

and 15th item lies in cf 21, hence M = 156