When finding percentiles, if the locator L is not a whole number, one procedure is to interpolate so that a locator of 23.75, for example, leads to a value that is 3/4 of the way between the 23rd and 24th scores. Use this method of interpolation to find P75 for the set of test scores below. $$\begin{array} { l l l l l l }
51 & 54 & 64 & 68 & 72 & 74 \
78 & 83 & 91 & 94 & 99 &
\end{array}$$
A) 83
B) 85
C) 87
D) 91

Question

When finding percentiles, if the locator L is not a whole number, one procedure is to interpolate so that a locator of 23.75, for example, leads to a value that is 3/4 of the way between the 23rd and 24th scores. Use this method of interpolation to find P75 for the set of test scores below. $$\begin{array} { l l l l l l } 
51 & 54 & 64 & 68 & 72 & 74 \
78 & 83 & 91 & 94 & 99 &
\end{array}$$
A) 83
B) 85
C) 87
D) 91

Quizplus · Accepted Answer

To find P75, calculate L = 0.75 * 11 = 8.25. Interpolate between the 8th (83) and 9th (91) scores: 83 + 0.25 * (91 - 83) = 85.

When Finding Percentiles, If the Locator L Is Not a Whole