ThoughtCo
thoughtco.com โบ null-hypothesis-examples-609097
How to Formulate a Null Hypothesis (With Examples)
May 7, 2024 - It's essentially the opposite of the null hypothesis because it assumes the claim in question is true. For the first item in the table above, for example, an alternative hypothesis might be "Age does have an effect on mathematical ability."
Washington State University
opentext.wsu.edu โบ carriecuttler โบ chapter โบ 13-1-understanding-null-hypothesis-testing
13.1 Understanding Null Hypothesis Testing โ Research Methods in Psychology
Explain for someone who knows nothing about statistics why the researchers would conduct a null hypothesis test. Practice: Use Table 13.1 to decide whether each of the following results is statistically significant. The correlation between two variables is r = โ.78 based on a sample size of 137. The mean score on a psychological characteristic for women is 25 (SD = 5) and the mean score for men is 24 (SD = 5).
Social psychology journal bans null hypothesis testing
That's not what I was expecting to read. Sure, some journals have banned or limited significance testing. (The American Journal of Public Health did it for a while in the 80s, and Epidemiology has a strong reporting policy.) And Psychological Science recently announced their support for " the new statistics ," meaning an emphasis on effect sizes and confidence intervals instead of p values. But I haven't heard anyone seriously advocate tossing out confidence intervals as well, and then cast doubt on Bayesian statistics too. I don't see how working with solely descriptive statistics will make results more reliable or easier to interpret. Even if CIs are not perfect, surely they're better than providing descriptive point estimates alone? edit: I skimmed the first author's previous paper on Bayesian statistics (Trafimow 2005). It argues that (a) we don't always know a good prior and (b) even then, a flat prior may not make sense, because we don't know if all events are really equally likely. That may be true, but with sufficient data, how does that really matter? Do we really need the prior distribution to be "accurate", whatever that means, or just not obviously stupid? More on reddit.com
Null hypothesis and Alternative Hypothesis
Hi! So, yours is actually a sophisticated question that masquerades as a simple one, so I'll try to answer this in a way that conveys the concept while perhaps alluding to some of its problems. At its heart, the null hypothesis is a sort of "straw man" that is defined by a researcher at the beginning of an experiment that usually represents a state of affairs that would be expected to occur if the researcher's proposal were false. Note that a null hypothesis is entirely imaginary, and it has nothing to do with the actual state of the world. It is contrived, usually to show that the actual state of the world is inconsistent with the null hypothesis. Suppose a researcher is trying to determine whether the heights of men and women are different. A suitable null hypothesis might be that the difference of the two population averages (height of men and height of women) is equal to zero. Then the researcher would conduct his or her experiment by measuring the heights of many men and women. When it comes time to draw a statistical conclusion, he or she will compute the probability that the observed data (the set of heights) could have come from the null hypothesis (i.e., a world where there is no difference). This probability is called a "p-value". Conceptually, this is similar to a "proof by contradiction," in which we assert that, if the probability is very small that the data could have originated from the null hypothesis, it must not be true. This is what is meant by "rejecting the null hypothesis". It is different from a proof by contradiction because rejecting the null proves nothing, except perhaps that the null is unlikely to be the source of the observed data. It doesn't prove that the true difference is 5 inches, or 1 inch, or anything. Because of this, rejecting the null hypothesis is in NO WAY equivalent to accepting an alternative hypothesis. Usually, in the course of an experiment, we observe a result (such as the observed height difference, perhaps it is ~5 inches) that, once we reject, replaces the hypothesized value of 0 under the null. However, we DON'T know anything about the probability that our observed value is "correct", which is why we never say that we have "accepted" an alternative. I actually hesitate to discuss an "alternative" hypothesis because most researchers never state one and it doesn't matter for the purposes of null hypothesis significance testing (NHST). It is just the name given to the conclusion drawn by the researchers after they have rejected their null hypothesis. Philosophically, there is an adage that data can never be used to prove an assertion, only to disprove one. It includes an analogy about a turkey concluding that he is loved by his human family and is proven wrong upon being slaughtered on Thanksgiving. I'll include a link if I can find it. Now, think about this: The concept of rejecting a null hypothesis probably seems very reasonable as long as we are careful not to overinterpret it, and this is how NHST was performed for decades. But consider - what is the probability that the null hypothesis is true in the first place? In other words, how likely is it that the difference between mens' and womens' heights is equal to zero? I propose that the probability is exactly zero, and if you disagree then I will find a ruler small enough to prove me correct. The difference can never be equal to exactly zero (even though this is the "straw man" that our experiment refutes), so we are effectively testing against a hypothesis that can never be true. Rejecting a hypothesis we already know to be false tells us nothing important ("the data are unlikely to have come from this state that cannot be true"). And since every null hypothesis is imaginary, it is suggested that any null hypothesis can be rejected with enough statistical power (read:sample size). Often a "significant" result says more about a study's sample size than it does about the study's findings, even though the language used in papers/media suggests to readers that the findings are more "important" or "likely to be correct". This has, in part, led to a reproducibility crisis in the sciences and, for some, an undermining of subject-matter-experts' trust in the use of applied statistics. More on reddit.com
Videos
03:45
Null Hypothesis | Definition & Examples - Video | Study.com
24:45
Psychology Statistics: Hypothesis Testing Made Easy - YouTube
14:41
Hypothesis Testing and The Null Hypothesis - YouTube
Examples of null and alternative hypotheses (video)
05:01
Hypothesis | Null, Alternative, Non Directional and Directional ...
04:15
A Level Psychology - Types of Hypothesis - YouTube
Ai-therapy
ai-therapy.com โบ psychology-statistics โบ hypothesis-testing
AI-Therapy | Statistics for Psychologists | Hypothesis Testing
A two-tailed version of the null hypothesis above is "exercise has an impact on mood". In this case, we suspect there is a relationship between exercise and happiness, but we're not sure if the impact will be positive or negative. Due to naturally occuring variablilty, two seperate measurements (even of the same phenomenon) will almost always give different results. For example, assume I measure my happiness after a run on Monday, and I measure it again after a run on Wednesday.
AlleyDog
alleydog.com โบ glossary โบ definition.php
Null Hypothesis Definition | Psychology Glossary | Alleydog.com
Null Hypothesis: Roses do not exhibit greater rate of growth when planted in soil rather than compost. Ok, these are lame, but they make the point. Let's say the researcher collects and analyzes the data, and the results are statistically significant at the 99% level (the data show that roses ...
Frontiers
frontiersin.org โบ articles โบ 10.3389 โบ fnhum.2017.00390 โบ full
Frontiers | When Null Hypothesis Significance Testing Is Unsuitable for Research: A Reassessment
August 3, 2017 - If the null hypothesis is true in all tests we run then FDR = FWER while if there are situations with true alternative hypotheses then FDR < FWER (see Table 3 for example). Also, various other FDR and FWER measures can be derived (see the above cited reviews). It can be argued that controlling FDR is more useful in research where a very large number of tests are carried out routinely, like neuro-imaging or genetics but less useful in behavioral psychological and social science research where fewer hypotheses may be tested at any one time and accepting any single hypothesis as statistically significant may have large impact on inferences (Gelman et al., 2012).
Statistics By Jim
statisticsbyjim.com โบ home โบ blog โบ null hypothesis: definition, rejecting & examples
Null Hypothesis: Definition, Rejecting & Examples - Statistics By Jim
November 7, 2022 - For these tests, the null hypothesis states that there is no difference between group proportions. Again, the experimental conditions did not affect the proportion of events in the groups. P is the population proportion parameter that youโll need to include. For example, a vaccine experiment compares the infection rate in the treatment group to the control group.
Open Textbook BC
opentextbc.ca โบ researchmethods โบ chapter โบ understanding-null-hypothesis-testing
Understanding Null Hypothesis Testing โ Research Methods in Psychology โ 2nd Canadian Edition
October 13, 2015 - Explain for someone who knows nothing about statistics why the researchers would conduct a null hypothesis test. Practice: Use Table 13.1 to decide whether each of the following results is statistically significant. The correlation between two variables is r = โ.78 based on a sample size of 137. The mean score on a psychological characteristic for women is 25 (SD = 5) and the mean score for men is 24 (SD = 5).
Paperpal
paperpal.com โบ home โบ how to write a hypothesis? types and examples
How to Write a Hypothesis? Types and Examples | Paperpal
October 7, 2025 - For example, โThere is a positive association between physical activity levels and overall health.โ A causal hypothesis, on the other hand, expresses a cause-and-effect association between variables. For example, โLong-term alcohol use causes liver damage.โ ยท Null: Claims that the original hypothesis is false by showing that there is no relationship between the variables.
Explorable
explorable.com โบ null-hypothesis
Null Hypothesis - The Commonly Accepted Hypothesis
Despite this, many researchers neglect the null hypothesis when testing hypotheses, which is poor practice and can have adverse effects. ... H1: Tomato plants exhibit a higher rate of growth when planted in compost rather than in soil. ... H0: Tomato plants do not exhibit a higher rate of growth when planted in compost rather than soil. It is important to carefully select the wording of the null, and ensure that it is as specific as possible. For example, the researcher might postulate a null hypothesis:
ThoughtCo
thoughtco.com โบ definition-of-null-hypothesis-and-examples-605436
What Is the Null Hypothesis? Definition and Examples
June 9, 2025 - The other way to state the null hypothesis is to make no assumption about the outcome of the experiment. In this case, the null hypothesis is simply that the treatment or change will have no effect on the outcome of the experiment. For this example, it would be that reducing the number of workouts would not affect the time needed to achieve weight loss:
Simply Psychology
simplypsychology.org โบ research methodology โบ research hypothesis in psychology: types, & examples
Research Hypothesis In Psychology: Types, & Examples
December 13, 2023 - The null hypothesis states that there will be no significant difference in the amount recalled on a Monday morning compared to a Friday afternoon. Any difference will be due to chance or confounding factors. Memory: Participants exposed to classical music during study sessions will recall more items from a list than those who studied in silence. Social Psychology: Individuals who frequently engage in social media use will report higher levels of perceived social isolation compared to those who use it infrequently.
Monash University
monash.edu โบ psychology research portal โบ research process โบ 2. investigate your research topic โบ d. produce a research proposal โบ aims and hypotheses
Aims and Hypotheses - Psychology Research Portal
The null hypothesis states that there is no relationship between the two variables being studied (one variable does not affect the other).
Fiveable
fiveable.me โบ all key terms โบ intro to psychology โบ hypothesis testing
Hypothesis Testing - (Intro to Psychology) - Vocab, Definition, Explanations | Fiveable | Fiveable
By formulating a null hypothesis ... statistically test these hypotheses. For example, in evaluating the effectiveness of a new therapy for depression, the null hypothesis might be that the therapy has no effect on symptoms, while the alternative hypothesis would be that the ...