question about usmle world item

[Brickhouse]

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Isn't the median the middle of a range of numbers? so the middle of 100 and 240 is 170? and the mean is the average. so if you have ten numbers about the same and add a hugely large outlier, your median will be most affected, yes your mean will move a little higher but the median is now between the highest and lowest numbers which will be huge. what am I missing?😕 please don't flame me if I'm missing something so obvious it's laughable, which I obviously am because 77% of students got the question right..... thanks for your help, future doctors.

 

[felipe5]

hey so the median is easy to see if you just picture all of the numbers in a row...the median value would be 7 in the following set 5, 6, 7, 8, 9. in that question since there are 10 numbers all inb/w 100-120, the median should definitely be somewhere around 110ish and won't budge much if you add a large number to the set....but the median (average) will if you add a large outlier. so median=middle value in a set, mode=number appearing the most and median=average. hope this helps!

 

[Brickhouse]

hey so the median is easy to see if you just picture all of the numbers in a row...the median value would be 7 in the following set 5, 6, 7, 8, 9. in that question since there are 10 numbers all inb/w 100-120, the median should definitely be somewhere around 110ish and won't budge much if you add a large number to the set....but the median (average) will if you add a large outlier. so median=middle value in a set, mode=number appearing the most and median=average. hope this helps!

Oh, I was thinking it was the halfway between the extremes....not the middle literally with all numbers lined up. I was figuring like the mean with two values, the highest and lowest. No wonder I got a "C" in algebra. But honestly, I can't believe I'm wasting my time with basic math when I should be memorizing the symptoms of vitamin overdose, which I'm also having trouble with.

Thanks felipe I thought I was totally nuts, I love you.

 

[Sage880]

Isn't the median the middle of a range of numbers? so the middle of 100 and 240 is 170?

I think I see where you're confused. It's only in the middle for a perfect distribution (bell curve). For any other set of numbers, it's the middle number in the set. Or the two middle numbers added together and divided by two for a set with an even number of values in it.

For a distribution, adding a huge number outside the range will affect the mean (average) the most, then shift the median just over to the next value or half way between, and the mode won't change.

Edit: Oops, took a long time to post my answer and got beat! Make sure you actually do get this stuff though. I had 2 questions on basically this concept on my exam.