how to find the median of this?is there any formula for that?
order number----| 10-14 | 15-19 | 20-24 | 25-29 | 30-34 | 35-39 |
frequency--------|__2 __|___5__|__9___|__21__|__ 9 __|__4__|
The median is the middle value, in this case n=50 therefore the median is between the 25th and 26th value.
But in your example we don't have actual values only the count of values within an interval. You can say that the median lies in the 25-29, some books will say the median is the middle of this interval, i.e. 27 but that raises new questions, is your data set discrete or continuous?