about decile... center, border, seventh, following, face

eyiqiong

What is the seventh decile of the following data points?> >>>

81> >	84> >	91> >	97	102	108	110	112	115	121
128	135	138	141	142	147	153	155	159	162

A) 141.7.

B) 141.0.

C) 142.0.

D) 141.5.

Your answer: C was incorrect. The correct answer was A) 141.7.

The formula for determining quantiles is: L_y = (n + 1)(y) / (100). (could you please explain this fomula?)Here, we are looking for the seventh decile (70 percent of the observations lie below) and the formula is: (21)(70)/(100) = 14.7. The seventh decile falls between 141.0 and 142.0, the fourteenth and fifteenth numbers from the left. Since L is not a whole number, we interpolate as: 141.0 + (0.70)(142.0 − 141.0) = 141.7.

ditto025

n是一共有n个观测值，这个例子中一共有20个观测值，y是分位数，以百分之九表示，这力是70，求seventh decile 是将数据从小到大排列之后，找出一个数，70％的数据小于这个数