Median vs. Second Quartile question

In summary, the conversation discusses the calculation of the second quartile and the median for a given list of numbers. The median and the second quartile are found to be the same value, with the calculation being done using the formula (n+1)/2. There is some confusion about whether the median is a single value or a range, but it is clarified that the inter-quartile range is the range of values between the first and third quartiles.
  • #1
Mathman2013
23
1

Homework Statement



Lets say I have a list of numbers.

income=[17000, 11000, 23000, 19999, 21000, 10000]

I sort them income_sorted=[10000, 11000, 17000, 19999, 21000, 23000]

Calculate med 2nd Quartile.

Homework Equations



Median_formula = (n+1)/2

The Attempt at a Solution



The second quartile and the median are most cases the same, so the median is 17000.

Then since there 6 observations.

I use the formula to Calculate the median and find that median = (6+1)/2 = 3.5

Meaning that the median is between the third and fourth number.

Find the average between those (17000+19999)/2 = 18500.

So my question aren't the median and 2.quartile suppose of a set of non-grouped observations suppose to equal each other? Or have I slept through statistics class?
 
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  • #2
Mathman2013 said:
So my question aren't the median and 2.quartile suppose of a set of non-grouped observations suppose to equal each other? Or have I slept through statistics class?

You are correct in saying that the median and the second quartile (Q2) are the exact same thing. I believe you calculated the median correctly the second time (by averaging terms 3 and 4). What led you to say that the median is 17000?
 
  • #3
[strike]I'm a bit rusty but I thought the median was a single value but a quartile was a range.[/strike]

I was wrong.
 
  • #4
CWatters said:
[strike]I'm a bit rusty but I thought the median was a single value but a quartile was a range.[/strike]

I was wrong.
maybe you're thinking about the inter-quartile range?

Sorry, just saw the edit now.
 
  • #5
Master1022 said:
maybe you're thinking about the inter-quartile range?

Sorry, just saw the edit now.
That was probably it.
 

FAQ: Median vs. Second Quartile question

What is the difference between median and second quartile?

The median is the middle value in a set of data when arranged in ascending or descending order. The second quartile is the value that divides the data into two equal halves, with 50% of the data points falling below it and 50% above it. In other words, the second quartile is the same as the median.

How is the median calculated?

To calculate the median, first arrange the data in ascending or descending order. If there is an odd number of data points, the median is the middle value. If there is an even number of data points, the median is the average of the two middle values.

What is the significance of median and second quartile in data analysis?

The median and second quartile are measures of central tendency, which describe the typical or average value in a set of data. They are useful in data analysis because they are not affected by extreme values, making them more representative of the data as a whole.

When should median be used instead of mean?

Median should be used instead of mean when the data is skewed or has extreme values. In these cases, the mean may be influenced by these extreme values and not accurately represent the central tendency of the data. The median, on the other hand, is not affected by extreme values and provides a more accurate measure of central tendency.

Can median and second quartile be used to compare two sets of data?

Yes, median and second quartile can be used to compare two sets of data. They provide a measure of central tendency that can be easily compared between different datasets, even if the datasets have different sizes or distributions.

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