Quartiles

[safirshahbaaz90]

Hi Tommy,

I have a rather silly question to ask regarding quartiles. According to the Manhattan Word problem prep book, in order to find the Q1, we have to find the median of the lower half of the data set. Similarly for Q3, we have to find the median of the upper half. For even number of data values, we can easily divide the set into 2. How should I split the list for odd number of values? For example, for a data set of 7 values, should I split the list (as 4 and 3) or (3 and 4).

Please help!

Regards,
Safir

[xerocoool]

Set A = {1,2,3,4,5,6,7,8,9}

Median = Q2 = 5

For odd number of values in the set : exclude Q2 from the lesser and greater set

lesser : {1,2,3,4}
Median = Q1 = 2+3/2 = 2.5

greater : {6,7,8,9}
Median = Q3 = 7+8/9 = 7.5

So,

Q1= 2.5
Q2 = 5
Q3 = 7.5
Least = 1
Greatest = 9

[tommywallach]

Hey Safir,

Xero is totally right. If there's an odd number of terms, just ignore the median and act as if there were an even number of terms.

-t

[safirshahbaaz90]

OK thanks Tommy and Xero!

[tommywallach]

Glad to help!

-t