Median in grouped data?

given that a frequency distribution of men in certain country in the age group when they get married in a particular year.





Age Frequency


16- 52


21- 161


26- 94


31- 32


36- 27


46- 14


56- 15


71- 0





estimate the median age men marry in that country...





can anyone tell what is meant by 16- , 21- and so on..|||That is a good question. The representation is not clear. If it is grouped data, then each group is defined by an interval, not a single number. For certain calculations, that interval is represented by a group mark, which is the midpoint of the interval. Sometimes we may use the upper boundary.





In this case, there is a hyphen after each age index. That might imply that it is the lower boundary. Consecutive groups are separated by 5, so that must be the width of each group. That would have the first group representing men who are greater than or equal to 16 years, but less than 21. Consult the source of the question if you can.





For a graphical median approximation, you will need a cumulative frequency distribution plot, using the upper boundary of each group. If I guessed correctly, the vertices will follow this pattern:





Age ... Cumulative Frequency


16 ... 0


21 ... 52


26 ... 213


...