R语言中，ERGM模型formula设置时，nodecov（）  nodeicov（） 和 nodeocov（）都是主效应吧？我看help文档解释见下面表格，我的问题是这几个效应分别怎么解释？ （望论坛内大神能举例说明） 如果我想分析某属性的发送效应我看是用sender，具体怎么用呢？我用sender("scale")提示下面错误：[color=rgb(196, 160, 0) !important]Error in `ergm_Init_abort()`: [color=rgb(196, 160, 0) !important]! In term ‘sender’ in package ‘ergm’: ‘base’ argument is not of any of the expected types: ‘numeric’.Run `[color=rgb(85, 87, 83) !important][url=]rlang::last_trace()[/url]` to see where the error occurred.

nodeicov(attr) (bin) nodeicov(attr, form) (val)

ergm

Main effect of a covariate for in-edges

directed frequently-used quantitative nodal attribute