There are two basic types of errors that can occur in hypothesis testing:

**Type A or 1 Error:**The null hypothesis is correct, but is incorrectly rejected.**Type B or 2 Error:**The null hypothesis is incorrect, but is not rejected.

The traditional way of explaining testing errors is with a table like the one shown below:

Typically, we’re more worried about Type A errors than Type B – rejecting a hypothesis that is not actually incorrect.

The chance of making a Type A error is referred to as the alpha risk or alpha level; the chance of making a Type B error is referred to as the beta risk or beta level.

Need more explanation? Khan Academy’s video does a good job of walking through Type A (or Type 1) errors:

## ASQ Six Sigma Green Belt Errors in Hypothesis Testing Questions:

**Question:** When an inspection process rejects conforming product, what type of error is being made?

(A) a

(B) b

(C) σ

(D) H0

**Answer:**

**Question:** Which of the following terms is used to describe the risk of a type I error in a hypothesis test?

(A) Power

(B) Confidence level

(C) Level of significance

(D) Beta risk

**Answer:**

**Question: **Which of the following is a commonly accepted level for alpha risk?

(A) 0.05

(B) 0.50

(C) 0.70

(D) 0.95

**Answer:**

## Comments (2)

Very helpful, a very good resourse

Glad it helped, Tim!