Measures of Position Quartiles Deciles Percentiles Quartiles Q

Measures of Position Quartiles, Deciles, Percentiles

Quartiles Q 1, Q 2, Q 3 divides ranked scores into four equal parts, using three quartiles. 25% 25% Q 1 Q 2 Q 3

Quartiles Q 1, Q 2, Q 3 Q 1=(n+1)/4 =Quartile(B 65: B 69, 1) where B 65: B 69 is range Q 2=2(n+1)/4 Q 3=3(n+1)/4 =Quartile(B 65: B 69, 3)

Deciles D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 8 , D 9 divides ranked data into ten equal parts DJ=j(n+1)/10

Deciles D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 8 , D 9 divides ranked data into ten equal parts 10% D 1 10% D 2 10% D 3 10% 10% D 4 D 5 D 6 10% D 7 D 8 10% D 9 10%

Percentiles 99 Percentiles or k th Percentiles (for a given number k)

Quartiles, Deciles, Percentiles Fractiles partitions data into approximately equal parts

Finding the Percentile Rank of a Given Score B=Number of observation below the value E=Number of observation equal to you N=Total number of observation

50, 65, 70, 72, 78, 80, 82, 84, 85, 86, 88, 90, 94, 96, 98, 99 (8+0. 5*2)*100/20=45 percentile Pk=k(n+1)/100 =PERCENTILE(A 128: A 147, 0. 45) Excel Function

Finding the Score Given a Percentile n number of scores in the data set k L Pk percentile being used locator that gives the position of a score kth percentile

Interquartile Range: Q 3 – Q 1 Semi-interquartile Range: Midquartile: Q 3 - Q 1+ Q 3 2 10 -90 Percentile Range: P 90 - P 10 2

Interquartile Range: Q 3 – Q 1 Semi-interquartile Range: Midquartile: Q 3 – Q 1+ Q 3 2 10 -90 Percentile Range: P 90 - P 10 2

Interquartile Range: Q 3 – Q 1 Semi-interquartile Range: Midquartile: Q 3 – Q 1 + Q 3 2 10 -90 Percentile Range: P 90 - P 10 2