# How to define variables correctly in qt function in R

for the question: If T has the Student's t distribution with 5 degrees of freedom, find t so that 2*P(T > t) = 0.09 I basically tried all of the following and the answer is wrong. I am not yet really so connected with the R syntax and don't know how to use qt. Any idea?

> 1-qt(0.045,5) [1] 3.097837 > qt(0.045,5) [1] -2.097837 > 1-qt(0.09,5) [1] 2.557869

## Answers

qt(0.09 / 2, 5, lower.tail = FALSE) ##[1] 2.097837

From ?qt:

lower.tail: logical; if TRUE (default), probabilities are P[X <= x], otherwise, P[X > x].