Chapter 1, Problem T1.3SPT

To determine

To find: the third quartile.

Answer to Problem T1.3SPT

44

Explanation of Solution

Given:

  

Formula used:

  $\text{Third}\text{Quartile = 3}\times \frac{\left(n+1\right)}{4}$

Calculation:

Values from the dot plot of the test score in ascending order

2, 8, 12, 12, 14, 15, 20, 21, 23, 23, 23, 23, 25, 28, 28, 28, 29, 30, 31, 33, 35, 36, 36, 37, 39, 42, 42, 44, 44, 44, 44, 46, 46, 47, 48, 48, 50, 50, 50

  $\begin{array}{c}\text{Third}\text{Quartile = 3}\times \frac{\left(n+1\right)}{4}\\ =3\times \frac{\left(40+1\right)}{4}\\ =30.75\end{array}$

=30^th position+0.75(31^st -30^th)

=44+0.75(44-44)

=44

Hence, the correct option is (c)