significance level: meaning, definition, pronunciation and examples
MediumTechnical/Formal
Quick answer
What does “significance level” mean?
In statistics, the predetermined probability threshold used to decide whether to reject the null hypothesis.
Audio
Pronunciation
Definition
Meaning and Definition
In statistics, the predetermined probability threshold used to decide whether to reject the null hypothesis.
The threshold for determining the statistical significance of a test result, representing the probability of rejecting the null hypothesis when it is actually true (Type I error). Commonly denoted by the Greek letter alpha (α).
Dialectal Variation
British vs American Usage
Differences
No significant difference in meaning or usage; the term is standard in international scientific and academic English.
Connotations
Identical in both varieties.
Frequency
Used with equal frequency in UK and US academic/statistical contexts.
Grammar
How to Use “significance level” in a Sentence
The test was performed at a significance level of 0.05.A significance level (α) was set at 0.01 prior to data collection.Vocabulary
Collocations
Usage
Meaning in Context
Business
Used in market research, A/B testing, and data analytics to determine if observed differences (e.g., in sales or engagement) are real or due to chance.
Academic
Core concept in research methodology across sciences, social sciences, and medicine for evaluating hypotheses.
Everyday
Almost never used in everyday conversation outside of specific statistical discussions.
Technical
Fundamental term in statistics, data science, econometrics, and experimental design.
Vocabulary
Synonyms of “significance level”
Strong
Neutral
Weak
Vocabulary
Antonyms of “significance level”
Watch out
Common Mistakes When Using “significance level”
- Confusing significance level with p-value. The level (α) is set before the test; the p-value is calculated from the data.
- Using 'significance level' to mean 'level of importance' in a non-statistical context.
- Stating 'the significance level was p<0.05' – the level *is* 0.05; p is the result.
FAQ
Frequently Asked Questions
Stricter. A lower significance level (like 0.01) makes it harder to reject the null hypothesis, requiring stronger evidence from the data.
0.05 (5%) is the most conventional and widely used significance level in many scientific fields, though 0.01 is also common for more stringent testing.
No, ideally it should be set before data collection and analysis to avoid bias (a practice known as 'p-hacking' or data dredging if done afterwards).
The significance level (α) is a pre-set cutoff. The p-value is calculated from the sample data. If the p-value is less than or equal to α, we reject the null hypothesis.
In statistics, the predetermined probability threshold used to decide whether to reject the null hypothesis.
Significance level is usually technical/formal in register.
Significance level: in British English it is pronounced /sɪɡˈnɪfɪkəns ˌlevəl/, and in American English it is pronounced /sɪɡˈnɪfɪkəns ˌlevəl/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “Crossing the significance threshold”
- “Passing the alpha bar”
Learning
Memory Aids
Mnemonic
Think of a 'significance level' as the 'significance speed limit' for data. If your p-value 'goes faster' (is lower) than this limit, you can reject the null hypothesis.
Conceptual Metaphor
A BARRIER or FILTER: The significance level acts as a filter that separates 'signal' (statistically significant results) from the 'noise' of random chance.
Practice
Quiz
What does a significance level of 0.05 represent?