Question

Find the first quartile, Q1, of the set of data.

90, 85, 88, 95, 100, 77, 85, 100, 97, 80, 90

Answer 1

First put them in ascending order

Answer 2

77, 80, 85, 85, 88, 90, 90, 95, 97, 100

Answer 3

Now find the median

Answer 4

Also you forgot 100 at the end

Answer 5

90

Answer 6

That's right

77, 80, 85, 85, 88, 90, 90, 95, 97, 100
\(\hspace{90pt}\uparrow\)
\(\hspace{80pt}\sf median\)

Answer 7

Now Q1 is in the middle of the part before the median
\(\large\sf \underbrace{77, 80, 85, 85, 88}, 90, 90, 95, 97, 100\)

Answer 8

Also have a look at this: http://www.mathsisfun.com/data/quartiles.html

Answer 9

how do i find Q3?

Answer 10

Q3 is the same but now for the part after the median
\(\large\sf 77, 80, 85, 85, 88, 90, \underbrace{90, 95, 97, 100, 100}\)

Answer 11

\(\Large\sf \overbrace{77, 80, 85, 85, 88}, 90,\overbrace{ 90, 95, 97, 100, 100}\)
\(\Large\hspace{44pt}\uparrow\hspace{53pt}\uparrow\hspace{55pt}\uparrow\)
\(\Large\sf\hspace{40pt}Q1\hspace{40pt}Q2 \hspace{45pt}Q3\)