Question 157888
<pre><font size = 4 color = "indigo"><b> 
Arrange the numbers smallest to largest:

#1  = 1.9
#2  = 2.0
#3  = 2.1
#4  = 2.9
#5  = 3.1
#6  = 3.4
#7  = 4.7
#8  = 5.0
#9  = 5.4
#10 = 6.8

There are 10 numbers in the list

To find {{{Q[1]}}}, which is called "the 25th percentile",
or "the 1st quartile"

Multiply {{{0.25}}} by {{{10}}}, getting {{{2.5}}}

Since that is not a whole number, we round up to 3.

So data value #3 is {{{Q[1]}}}.

So {{{first_quartile=Q[1]=2.1}}},

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To find {{{Q[2]}}}, which is called "the median", "the
50th percentile", or "the 2nd quartile"

 Multiply {{{0.50}}} by {{{10}}}, getting {{{5}}}

Since that is a whole number, we find the ordinary
average of data values #5 and #6:

So {{{Q[2]= second_quartile=median=(3.1+3.4)/2=6.5/2=3.25}}},

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To find {{{Q[3]}}}, which is called "the
75th percentile", or "the 3rd quartile"

Multiply {{{0.75}}} by {{{10}}}, getting {{{7.5}}}

Since that is not a whole number, we round up to 8.

So data value #8 is {{{Q[3]}}}.

So {{{third_quartile=Q[3]=5.0}}}

Edwin</pre></b></font>