Definition of Type II Error:
« Back to Glossary IndexType I and Type II errors are essentially the inverse of one another and cover the full possibility of errors in statistics. There is some debate as to which error is worse, with many leaning towards Type II.
What is a Type II error?
A Type II error is the kind of error that produces a false negative. It is also known as an error of omission.
3 drawbacks of a Type II error
There are some clear drawbacks to Type II errors that are worth noting:
1. Unavoidability
Uncertainties are always a part of making statistical decisions, which makes the risk of Type II errors unavoidable in hypothesis testing.
2. It means something was missed
When there is a Type II error, it means that you failed to conclude that there was an effect when there, indeed, was one.
3. Increasing test power opens up the chance for other errors
By increasing the power of a test, you lessen your chances of a Type II error, but increase your chances of a Type I.
Why are Type II errors important to understand?
Understanding Type II errors is important for the following reasons:
1. You will likely encounter them regularly
These types of errors are utilized often in such areas as engineering, computer science, and statistics.
2. Real-life consequences
There are some situations where a Type II error can have real-world consequences, so it is important to have an understanding of them.
3. Disapproval of hypothesis
Having a working knowledge of Type II errors will prepare you for the possibility of one occurring should a researcher disapprove of the outcome of a correct hypothesis.
An industry example of a Type II error
A very problematic example of a Type II error would be when a medical patient is given a negative result for a disease when, in fact, they are infected. This counts as a Type II error since, even though it is incorrect, we accept the findings of the test.
3 best practices when thinking about Type II errors
There are some practices to keep in mind in order to minimize the chance of Type II errors:
1. Minimize risk
By using careful planning in your study design, you run less risk of running into Type II errors.
2. Inverse relation to statistical power
The higher the statistical power of a study, the less likelihood of Type II errors.
3. Increasing sample size
To reduce the chance of encountering a Type II error, increasing the sample size or significance level is recommended.
Frequently Asked Questions (FAQ) about Type II errors
1. What is the difference between Type I errors and Type II errors
The main difference between these two errors is that Type I is related to false positives while Type II is related to false negatives.
2. What factors influence a Type II error?
The magnitude of the risk of an error is influenced by such factors as pre-set alpha level and sample size.
3. What is statistical power as related to Type II errors?
In statistics, power is referencing the likeliness of a hypothesis test being able to detect a true effect. Type II errors are more likely to be rejected by statistically powerful tests.
Avoiding Type II errors
As stated above, Type II errors are sometimes unavoidable. You can reduce your chances of encountering them by increasing your sample size, statistical power, and level of significance.
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