Compute median from the below histogram.

Jeff, give me the green light and I will open a thread. it is really interesting what he does there on the graph. and you're right Jeff I am talking about the screenshot from khan academy, not about this exercise. here
 
Well I shall answer your question without doing that, but please, in the future, don’t stick multiple problems in the same thread and don’t go ask questions that require looking across multiple pages.

He gets the 9 from reading the scale on the left hand side of the histogram.

If you want to discuss this video in more detail, please start a new thread with aa link. I really do not think it says anything Harry has not already explained in this thread.
 
Eddy, the vertical scale (ie the y-axis) on a histogram always represents the frequency of the scores (on the x-axis). The frequency is the number of times those scores occur. That's exactly what you have done in your post where you list all the datapoints.
Your original question is quite simple as long as you understand exactly what a histogram is telling you.
In summary , all you need to do is:
1. Find the total number of datapoints by adding all the frequencies (represented by the heights of the bars on the histogram). 90
2. Calculate the position of the median. Since 90 is even, the median is halfway between the 45th and 46th datapoint.
3. Find these two datapoints. There is no need to list them all. You can see from the histogram that the datapoints in positions 1 to 8 are 35, the datapoints in positions 9 to 17 (17 =8+9 the sum of the first two frequencies) are 36, the datapoints in positions 18 to 31 (31=8+9+14 sum of first three frequencuies) are 37, the datapoints in positions 32 to 50 (sum of first 4 frequencies) are 38. So the datapoints you want (ie the 45th and 46th) must be 38 and 38.
4. Calculate the median. The median is 38.
 
Harry_the_cat said:
Eddy, the vertical scale (ie the y-axis) on a histogram always represents the frequency of the scores (on the x-axis). The frequency is the number of times those scores occur. That's exactly what you have done in your post where you list all the datapoints.
Your original question is quite simple as long as you understand exactly what a histogram is telling you.
In summary , all you need to do is:
1. Find the total number of datapoints by adding all the frequencies (represented by the heights of the bars on the histogram). 90
2. Calculate the position of the median. Since 90 is even, the median is halfway between the 45th and 46th datapoint.
3. Find these two datapoints. There is no need to list them all. You can see from the histogram that the datapoints in positions 1 to 8 are 35, the datapoints in positions 9 to 17 (17 =8+9 the sum of the first two frequencies) are 36, the datapoints in positions 18 to 31 (31=8+9+14 sum of first three frequencuies) are 37, the datapoints in positions 32 to 50 (sum of first 4 frequencies) are 38. So the datapoints you want (ie the 45th and 46th) must be 38 and 38.
4. Calculate the median. The median is 38.
Click to expand...
Thanks a lot, Harry.
 
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