[R] solved

[ronggui]

i have find the answer to this question.
sorry for my overlook the information about it in internet.

> 2,as some textbook say,when using fisher's method,"we proceed by assuming that the within-group covariance structure for our data is the same across groups",so we need test for equailty of covariance matrices. my question is :when i using lda,should i test equailty of covariance matrices first? and can R do these?

the box's m test is the way for this purpose,but the test does not have good property.so it is not worthwhile for us the do the test.