我在做期末作业，但是这道题不会弄a，我有三个variable，题目要求Find the 95% joint confidence region for all the three regression coefficients associated with Price, Age, and Income (i.e. beta =[beta(price) beta(Age) beta(Income)]’).

大神们，帮帮我啊，程序怎么写啊，如果是两个，就是做椭圆图，现在是三个，难道要做个面出来？