John rejected his null hypothesis in a right-tailed test for a mean at α = .025 because his critical t value was 2.000 and his calculated t value was 2.345.We can be sure that:
A) John did not commit Type I error.
B) John did not commit Type II error.
C) John committed neither Type I nor Type II error.
D) John committed both Type I and Type II error.

Question

Quizplus · Accepted Answer

John rejected the null hypothesis because his calculated t value (2.345) was greater than the critical t value (2.000), indicating that the test statistic fell into the rejection region. This means he did not commit a Type II error, which occurs when a false null hypothesis is not rejected. However, we cannot be sure about Type I error without knowing the true state of the null hypothesis.

John Rejected His Null Hypothesis in a Right-Tailed Test for a Mean