Linear Regression and storing results in data frame [duplicate]

Answer 1

Here is a solution using dplyr and tidy() from the broom package. tidy() converts various statistical model outputs (e.g. lm, glm, anova, etc.) into a tidy data frame.

library(broom)
library(dplyr)

data <- data_frame(a, b, c)

data %>% 
  group_by(a) %>% 
  do(tidy(lm(b ~ c, data = .))) %>% 
  select(variable = a, t_stat = statistic) %>% 
  slice(2)

#   variable     t_stat
# 1        a  1.6124515
# 2        b -0.1369306
# 3        c  0.8000000  

Or extracting both, the t-statistic for the intercept and the slope term:

data %>% 
  group_by(a) %>% 
  do(tidy(lm(b ~ c, data = .))) %>% 
  select(variable = a, term, t_stat = statistic)

#   variable        term     t_stat
# 1        a (Intercept)  1.2366939
# 2        a           c  1.6124515
# 3        b (Intercept)  2.6325081
# 4        b           c -0.1369306
# 5        c (Intercept)  1.4572335
# 6        c           c  0.8000000