Here's how to find the mean: first count how many numbers there are, and remember that. Then add all the numbers up. Divide this sum by your count and you'll have the mean.
Here's how to find the median: sort the data in either ascending or descending order. Then find which one is in the "middle". That's the median. If there isn't one specific middle because there were an even number of elements, then take the mean of the two middle elements.
Here's the mean: There are 24 numbers. Their sum is 203+245+237+233+90+100+100+277+265+264+265+285+288+291+290+300+224+200+257+290+279+266+288=5537 The mean is 5537/24=230.708
The median is a bit long but you know how to do it.
