Question

Introductory Econometris: A Modern Approach 4th edition, Chapter 17 Problem 1CE: What is the command in R in order to check if β0=0.5? I can see in the solution that it makes a wald test to show the t statistic and the value in order to reject Ho, but i do not know how to extract these in R.

Answer 1

The below commands can be used to do one tailed t test in R.

data(cars)

head(cars)

model <- lm(dist ~ speed, data=cars)

summary(model)

b0=0.5 ### Hypothesized value of slope

### Calculate the test statistic

tstat <- (coef(summary(model))[1,1]-b0)/coef(summary(model))[1,2]

tstat

2*pt(tstat, 48, lower.tail=FALSE) ## 48 is the degrees of freedom from the model summary

### If the p-value in the last command is less than 0.05, we reject the null hypothesis