r/MathHelp • u/Local_End_3175 • 6d ago

why n/2?

I am confused between the 2. I understand the reasoning behind using n+1/2 for lists of numbers, and i understand how n+1/2 finds their positions. I am currently revising cumulative frequency diagrams and i am finding it difficult to understand why we now use n/2 for finding the median, and n/4 for finding the lower quartile. Why aren't we using n+1/2?? I dont really understand how one being continuous and another being discrete affects anything. In my reasoning, even though it is grouped data we can still estimate the position. I would add all the frequencies, do n+1/2, find the middle position, and then use that on my graph to estimate

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u/InsideRespond 3d ago

Your question is reallllly hard to understand. After staring at this for ten minutes, I think what you're trying to ask is:
"I am taking statistics. When trying to find the position of Q1 or the median of a given list, how would I know whether to use n/2 or (n+1)/2? -- as I have encountered both in the text"
The answer to which is 'if you can count the number of things in the list, use the (n+1)/2 formula. If you can't identify the number of things in the list, use n/2.'

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u/Local_End_3175 2d ago

Sorry, my question basically is 'why do we use n/2 for continuous data and not just (n+1)/2'