建议;1.看书2.实战。软件输出结果会让人看懂。你就做的时候做两种，一种有变量，一种没有不就行了

就是输出结果看不明白才来问一下嘛...有谁知道啊？trim的range是0到0.5，这个到底是什么含义啊？

mean {base}        R Documentation
Arithmetic Mean

Description

Generic function for the (trimmed) arithmetic mean.

Usage

mean(x, ...)

## Default S3 method:
mean(x, trim = 0, na.rm = FALSE, ...)
Arguments

x       
An R object. Currently there are methods for numeric/logical vectors and date, date-time and time interval objects. Complex vectors are allowed for trim = 0, only.

trim       
the fraction (0 to 0.5) of observations to be trimmed from each end of x before the mean is computed. Values of trim outside that range are taken as the nearest endpoint.

na.rm       
a logical value indicating whether NA values should be stripped before the computation proceeds.

...       
further arguments passed to or from other methods.

Value

If trim is zero (the default), the arithmetic mean of the values in x is computed, as a numeric or complex vector of length one. If x is not logical (coerced to numeric), numeric (including integer) or complex, NA_real_ is returned, with a warning.

If trim is non-zero, a symmetrically trimmed mean is computed with a fraction of trim observations deleted from each end before the mean is computed.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

weighted.mean, mean.POSIXct, colMeans for row and column means.

Examples

x <- c(0:10, 50)
xm <- mean(x)
c(xm, mean(x, trim = 0.10))

谢谢，我已经弄明白了，就是从vector两边减掉对应比例的数据。