In this video, we are going to explain what a hypothesis is in the context of a typical
dissertation, thesis or research paper. A hypothesis in this context is also sometimes
called a research hypothesis or scientific hypothesis. So do not worry if you have
encountered slightly different terminology. If you are new to the oftentimes intimidating world of
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You can find the link to those in the description.
So what exactly is a hypothesis? Well, let us start with the general definition of hypothesis
before we get more granular and explore research hypothesis specifically. According to the
Cambridge dictionary, a hypothesis is an idea or explanation for something that is based on
known facts but has not yet been proved. In other words, a hypothesis
is a statement that proposes an explanation for how or why something works or the relationship
between two or more things based on existing knowledge or some reasonable assumptions.
For example, a hypothesis could look something like this. Sleep impacts academic performance.
This statement predicts that academic performance will be influenced by the amount and or quality of
sleep a student engages in. Sounds reasonable, right? It is based on reasonable assumptions
underpinned by what we currently know about sleep and health from the existing literature. So
loosely speaking we could call it a hypothesis at least by the dictionary definition. Unfortunately,
however that is not quite sophisticated enough to describe a research hypothesis.
In the world of academic research, a statement needs a few more criteria to constitute a true
research hypothesis. In particular, a hypothesis statement needs to be clear,
specific and testable. Let us take a look at each of these criteria. Number one specificity
and clarity. A good research hypothesis needs to be extremely clear and articulate about both what
is being assessed or who or what variables are involved and the expected outcome. For example
a difference between groups or a relationship between variables etcetera. Let us stick with
our sleepy students example and look at how this statement could be more specific
and clear. Hypothesis, students who sleep at least eight hours per night will on average
achieve higher grades in standardised tests than students who sleep less than eight hours a night.
As you can see the statement is very specific as it identifies the variables involved sleep hours
and test grades. The parties involved, two groups of students as well as the predicted relationship
type a positive relationship. There is no ambiguity or uncertainty about who or what is
involved in the statement and the expected outcome is clear. Contrast that to the original hypothesis
we looked at sleep impacts academic performance and you can see the difference. Sleep and academic
performance are both comparatively vague and there is no indication of what the expected relationship
direction is more sleep or less sleep. So as you can see specificity and clarity are key. Right,
let us look at the next requirement. Number two, testability. A statement must be testable to
qualify as a research hypothesis. If it is not testable it is not a hypothesis simple as that.
Testability means that you must be able to collect observable data in a scientifically,
rigorous fashion to assess whether it supports the hypothesis or not. In other words,
there needs to be a way to prove or disprove the statement. For example, considering the previous
hypothesis we could test this hypothesis by undertaking a quantitative study involving
two groups of students one that gets eight or more hours of sleep per night for a fixed period
and one that gets less. We could then compare the standardised test results for both groups
to see if there is a statistically significant difference. In other words, this hypothesis is
very testable. Again if you compare this to the original hypothesis we looked at sleep impacts
academic performance you can see that it would be quite difficult to test that statement primarily
because it is not specific enough. Simply put if you cannot test it, it is not a hypothesis.
All right let us quickly recap. A research hypothesis also sometimes called a scientific
hypothesis is a statement about an expected relationship between variables or explanation
of an occurrence. To qualify as a research hypothesis the statement needs to be very clear,
specific and testable. So when you write up the hypothesis for your dissertation or
thesis make sure that your statements meet these criteria. If you do you will not only have
rock-solid hypothesis but you will also ensure a clear focus for your entire research project. One
more thing you may have also heard the terms null hypothesis, alternative hypothesis or H0 thrown
around. At a simple level, the null hypothesis is the counterproposal to the original hypothesis.
For example, if the hypothesis predicts that there is a relationship between two variables,
for example, sleep and academic performance the null hypothesis would predict that there is no
relationship between those variables. At a more technical level, the null hypothesis proposes that
no statistical significance exists in a set of given observations and that any differences are
due to chance alone. If that sounds like gibberish to you do not stress you can check out our video
explaining quant analysis basics where we unpack the lingo, link in the description.
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