Can you ever prove the null hypothesis is true?

No, you can only fail to reject it. A lack of evidence against it is not proof that it is true.

What is the symbol for the null hypothesis?

It is conventionally denoted as H₀ (H-sub-zero).

Is the null hypothesis always 'no difference'?

Typically yes, but it can be a statement of a specific value (e.g., 'the mean is equal to 10'). Its key feature is that it is a precise, testable statement.

Why is it called 'null'?

'Null' comes from the Latin 'nullus' meaning 'none.' It represents the hypothesis of no effect, no difference, or no relationship.

null hypothesis

C1-C2 / Low-frequency technical term

UK/ˌnʌl haɪˈpɒθəsɪs/US/ˌnʌl haɪˈpɑːθəsɪs/

Formal, Academic, Technical (Statistics/Science)

My Flashcards

Definition

Meaning

In statistics, the default hypothesis that there is no significant effect or relationship between variables, which is tested against an alternative hypothesis.

A statement or assumption that any observed difference, correlation, or effect in a study is due to chance or random variation, rather than a genuine underlying cause. It serves as a baseline for statistical testing.

Linguistics

Semantic Notes

Not used in everyday language. It is a foundational concept in inferential statistics (hypothesis testing). Often contrasted with the 'alternative hypothesis' (H₁). The goal is to gather evidence to 'reject' or 'fail to reject' the null hypothesis.

Dialectal Variation

British vs American Usage

Differences

No significant differences in meaning or usage. Spelling of related terms may differ (e.g., 'analyse' vs. 'analyze').

Connotations

Identical technical connotations in both varieties.

Frequency

Equal frequency within academic/statistical contexts in both the UK and US.

Vocabulary

Collocations

strong

test the null hypothesisreject the null hypothesisfail to reject the null hypothesisnull hypothesis states

medium

formulate a null hypothesisnull hypothesis of no differencenull hypothesis is true

weak

challenging the null hypothesisevidence against the null hypothesisprobability under the null hypothesis

Grammar

Valency Patterns

The null hypothesis (that) + CLAUSEthe null hypothesis of + NOUN PHRASEthe null hypothesis for + NOUN PHRASE

Vocabulary

Synonyms

Strong

no-effect hypothesis

Neutral

default hypothesisstatistical hypothesisH₀

Weak

straw-man hypothesis (informal/pejorative in some contexts)

Vocabulary

Antonyms

alternative hypothesisresearch hypothesisH₁

Phrases

Idioms & Phrases

“[No idioms exist for this technical term]”

Usage

Context Usage

Business

Used in market research, A/B testing, and data analysis to validate business decisions. Example: 'We tested the null hypothesis that the new website design has no impact on conversion rates.'

Academic

Core term in research papers across sciences, social sciences, and medicine. Example: 'The study failed to reject the null hypothesis of no association between the variables.'

Everyday

Extremely rare. Might be paraphrased as 'the assumption it makes no difference.'

Technical

Central to statistical inference, experimental design, and p-value calculation. Example: 'The p-value represents the probability of obtaining the observed results if the null hypothesis is true.'

Examples

By Part of Speech

verb

British English

[No standard verb form. The verb 'hypothesise' is related but not specific to null hypothesis.]

American English

[No standard verb form. The verb 'hypothesize' is related but not specific to null hypothesis.]

adverb

British English

[No standard adverb form]

American English

[No standard adverb form]

adjective

British English

null-hypothetical framework
the null-hypothesis testing procedure

American English

null-hypothetical framework
the null-hypothesis testing procedure

Examples

By CEFR Level

[Too advanced for A2 level]

[Too advanced for B1 level]

Scientists often start with a null hypothesis that a new drug has no effect.
If the data is strong, we can reject the null hypothesis.

The p-value was 0.03, allowing us to reject the null hypothesis at the 5% significance level.
Our null hypothesis posited that there would be no correlation between income and life satisfaction in the sampled population.

Learning

Memory Aids

Mnemonic

Think of NULL as meaning 'zero' or 'nothing.' The NULL HYPOTHESIS is the hypothesis of 'no difference' – it's the 'nothing to see here' starting point that researchers try to disprove.

Conceptual Metaphor

INNOCENCE UNTIL PROVEN GUILTY (The null hypothesis is treated as 'innocent' (true) unless strong statistical evidence proves it 'guilty' (false).)

Watch out

Common Pitfalls

Translation Traps (for Russian speakers)

Avoid direct translation of 'null' as 'нулевой' without context. The standard term is 'нулевая гипотеза'.
Do not confuse with 'alternative hypothesis' ('альтернативная гипотеза').
The concept of 'failing to reject' is not the same as 'accepting' the null hypothesis – a key nuance often lost.

Common Mistakes

Saying 'we accept the null hypothesis' instead of the correct 'we fail to reject the null hypothesis.'
Confusing the null hypothesis with the alternative hypothesis.
Using it in non-statistical contexts where 'assumption' or 'default position' would be more appropriate.

Practice

Quiz

Fill in the gap

In statistical testing, researchers aim to gather evidence against the .

Multiple Choice

What does rejecting the null hypothesis typically imply?

FAQ

Frequently Asked Questions

: No, you can only fail to reject it. A lack of evidence against it is not proof that it is true.
: It is conventionally denoted as H₀ (H-sub-zero).
: Typically yes, but it can be a statement of a specific value (e.g., 'the mean is equal to 10'). Its key feature is that it is a precise, testable statement.
: 'Null' comes from the Latin 'nullus' meaning 'none.' It represents the hypothesis of no effect, no difference, or no relationship.