计算方法有很多种，而不是两种。

没有绝对的标准是哪个更加好。

那楼上的更倾向于用那种?

请教:

还有那些方法??

四分位点的计算方法有很多种吗？

请高人指点

在R中?quantile可以看到至少有9种
*Discontinuous sample quantile types 1, 2, and 3*

     Type 1 Inverse of empirical distribution function.

     Type 2 Similar to type 1 but with averaging at discontinuities.

     Type 3 SAS definition: nearest even order statistic.

     *Continuous sample quantile types 4 through 9*

     Type 4 p(k) = k / n. That is, linear interpolation of the
          empirical cdf.


     Type 5 p(k) = (k - 0.5) / n. That is a piecewise linear function
          where the knots are the values midway through the steps of
          the empirical cdf. This is popular amongst hydrologists.


     Type 6 p(k) = k / (n + 1). Thus p(k) = E[F(x[k])]. This is used by
          Minitab and by SPSS.


     Type 7 p(k) = (k - 1) / (n - 1). In this case, p(k) =
          mode[F(x[k])]. This is used by S.


     Type 8 p(k) = (k - 1/3) / (n + 1/3). Then p(k) =~ median[F(x[k])].
          The resulting quantile estimates are approximately
          median-unbiased regardless of the distribution of 'x'.


     Type 9 p(k) = (k - 3/8) / (n + 1/4). The resulting quantile
          estimates are approximately unbiased if 'x' is normally
          distributed.

[titter][titter]