why is r not returning coefficients in excel why does r return na why does r return na coefficient why would r return na as lm coefficient why does r use na coefficient why would r return na as a lm() coefficient? why would r return na instead of coefficient what is the coefficient for na why does r return na as coefficient why does r return the coefficient for na why does r use coefficient why would r return na as a lm() coefficient? why does r return na coefficient why do r r returns na as coefficient r returns coefficient na in a model why does r return na r why does r get na when calculating the coefficient why would r return na instead of coefficient what is the coefficient of lm in r why do r returns na coefficients