Determine the quartile or interquartile range as specified.
-The weights (in pounds)of 18 randomly selected adults are given below. Find the third quartile,
$\mathrm { Q } _ { 3 }$
$\begin{array} { l l l l l l } 120 & 165 & 187 & 143 & 119 & 132 \ 127 & 156 & 179 & 159 & 180 & 202 \ 114 & 146 & 151 & 168 & 173 & 144 \end{array}$
A)$173 \mathrm { lb }$
B) $174.5 \mathrm { lb }$
C) $176 \mathrm { lb }$
D) $170.5 \mathrm { lb }$

Question

Determine the quartile or interquartile range as specified.
-The weights (in pounds)of 18 randomly selected adults are given below. Find the third quartile, 
$\mathrm { Q } _ { 3 }$ 
$\begin{array} { l l l l l l } 120 & 165 & 187 & 143 & 119 & 132 \ 127 & 156 & 179 & 159 & 180 & 202 \ 114 & 146 & 151 & 168 & 173 & 144 \end{array}$  
A)$173 \mathrm { lb }$
B) $174.5 \mathrm { lb }$
C) $176 \mathrm { lb }$
D) $170.5 \mathrm { lb }$

Quizplus · Accepted Answer

To find the third quartile ($Q_3$), first, arrange the data in ascending order: 114, 119, 120, 127, 132, 143, 144, 146, 151, 156, 159, 165, 168, 173, 179, 180, 187, 202. With 18 data points, $Q_3$ is the value at the $3/4 \times 18 = 13.5$th position, which means we average the 13th and 14th values. The 13th and 14th values are both 168 and 173, so $Q_3 = (168 + 173) / 2 = 341 / 2 = 170.5$, indicating a mistake in calculation. Correctly, $Q_3$ is the value at the 14th position due to the method of calculation used here being incorrect for this context. The correct method is to directly take the 14th value for $Q_3$ when the data is ordered, which is 173.

Determine the Quartile or Interquartile Range as Specified Q3\mathrm { Q } _ { 3 }Q3​

Determine the Quartile or Interquartile Range as Specified $\mathrm { Q } _ { 3 }$