Directional Hypothesis (A Comprehensive Guide)


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Page last updated: 1/05/2020

Directional Hypothesis

A hypothesis is a recommended explanation for an unsolved event that does not fit into an existing accepted scientific theory.

The central idea of a hypothesis is that there is no encoded result.

For a hypothesis to be termed a scientific hypothesis, it has to be something that can be maintained or refuted throughout carefully crafted carrying out tests or examinations.

In this article, we will discuss the directional hypothesis. 

A scientific hypothesis is the initial building block in the scientific method.

Many explain it like a “knowledgeable guess,” based on previous information and observation.

Though this is factual, the description can be extended.

A hypothesis also includes an elucidation of why the guess may be accurate, according to the National Science Teachers Association.

A major purpose in this step in the scientific method is getting predictions from the hypotheses about the results of upcoming experiments, and then conducting those experiments to see whether they keep up the predictions.

A hypothesis is usually written in the form of if and then statement, according to the University of California.

This affirmation gives a possibility (if) and gives an explanation of what might happen because of the possibility (then).

The affirmation could also include “may.”

Examples of Hypothesis:

Here are a number of few examples of hypothesis statements:

  • If ginger repels parasites, then a dog that is given ginger every day will not get parasites.
  • Bacterial intensification may be affected by humidity levels in the air.
  • If a person gets 7 hours of sleep, then he will feel less fatigue than if he sleeps less.
  • If sugar causes cavities, then people who take a lot of sugary products may be more prone to cavities.
  • If UV light can damage the eyes, then maybe UV light is a cause of loss of sight.
Directional Hypothesis (A Comprehensive Guide)

Testing a Hypothesis:

Note that all of the statements, above, are testable.

The most important feature of a hypothesis is that something can be tested and that those tests can be replicated, according to Midwestern State University.

An example of an untestable statement is, “All people fall in love at least one time.”

The definition of love is subjective. Also, it would not be possible to question every person about their love life.

Though, an untestable statement can be reworded to make it testable.

For instance, the previous statement could be misrepresented to, “If love is an important emotion, some might consider that everyone should fall in love at least one time.”

With this affirmation, the researcher can survey a group of people to observe how many think people should fall in love at least one time.

A hypothesis is frequently examined by many scientists to make sure the reliability and authenticity of the experiment.

This procedure can take years, and in many cases, the hypothesis does not go anymore in the scientific method as it is hard to collect enough supporting confirmation.

The Evolution of a Hypothesis:

The majority of proper hypotheses comprise of the notion that can be associated and their relations tested.

A group of hypotheses comes as one to form a theoretical framework.

Because enough data and facts are gathered to maintain a hypothesis, it becomes an operational hypothesis, which is a high point on the way to appropriate theory.

Although hypotheses and theories are a lot confused, theories are the outcome of a tested hypothesis.

While hypotheses are thoughts and ideas, theories explain the conclusion of the testing of those ideas. 

“Theories are the traditions that we make logic of what we examine in the ordinary world. Theories are structures of thoughts and ideas that give details and interpret facts and data,” said Tanner.

Characteristics of Hypothesis:

Following are the characteristics of the hypothesis:

  • The hypothesis should be understandable and accurate so as to believe it to be consistent.
  • If the hypothesis is a relational hypothesis, then it should be stating the association between variables.
  • The hypothesis has to be precise and should have the capacity for performing more tests.
  • The method of rationalization of hypotheses has got to be very straightforward and it should also be understood that straightforwardness of hypotheses is not related to its importance.

Functions of Hypothesis:

The functions performed by the hypothesis are as follows:

  • Hypothesis helps in making experimentation and observation possible.
  • It becomes the beginning point for the inspection.
  • Hypothesis facilitates invalidating the observations.
  • It assists in directing the investigation in the right direction.

Hypothesis helps in Scientific Method:

Hypothesis helps the researcher to put down their thoughts and ideas directing how the research will take place.

The steps that are involved in the scientific method are as follows:

  • Construction of a question
  • Doing background research
  • Formation of a  hypothesis
  • Conducting an experiment
  • Collection of data
  • End result analysis
  • Summarizing the research
  • Discussing the results

Types of Hypothesis:

There are mostly six forms of hypothesis and they are as follows:

  • Simple hypothesis
  • Complex hypothesis
  • Directional hypothesis
  • Nondirectional hypothesis
  • Null hypothesis
  • Associative and causal hypothesis

Simple Hypothesis:

This shows a link between one dependent variable and an independent variable.

For instance, if you eat more junk food, you will gain weight faster.

Here, eating more junk food is an independent variable, while gaining weight is the dependent variable.

Complex Hypothesis:

This represents the association between two or more dependent variables and two or more independent variables.

Eating more vegetables and fruits leads to weight loss, clear skin, lowers the danger of many diseases such as heart disease, high blood pressure, and some cancers.

Directional Hypothesis:

A directional hypothesis shows how an examiner is rational and dedicated to a particular result.

The association between the variables can also foresee its nature.

For instance, children aged 4 years consumption proper food over a five years stage is having a higher IQ level than children not having an appropriate meal.

It shows the effect and the direction of the end product.

Nondirectional Hypothesis:

The non-directional hypothesis is used when there is no assumption concerned.

It is a statement that a connection exists between two variables, without foretelling the precise nature (direction) of the relationship.

Null Hypothesis:

The null hypothesis comes up with the statement which is opposing the hypothesis.

It is a negative statement, and there is no affiliation between independent and dependent variables.

The representation of the null hypothesis is denoted by “HO”.

Associative and Causal Hypothesis:

Associative hypothesis occurs, when there is a transformation in one variable, ending up a change in the other variable.

On the other hand, a causal hypothesis proposes a cause and effect relations between two or more variables.

Directional Hypothesis:

A directional hypothesis is a hypothesis test where a direction is specific (e.g. over or under a convinced verge).

For instance, you may be concerned in whether a hypothesized mean is larger than a definite number (you are an experiment in a positive direction on the numeral line), or you may want to identify if the mean is a smaller amount than that number (you are experimenting towards a negative direction).

The directional hypothesis is suitable in situations where you suppose a transformation that is positive or negative, not both.

A directional hypothesis is a guess made by a researcher concerning a positive or negative change, association, or differentiation between two variables of a population.

This forecasting is usually based on the past study, established theory, widespread knowledge, or literature on the subject matter. 

Keywords that differentiate a directional hypothesis are: 

  • higher 
  • lower 
  • more 
  • less
  • increase 
  • decrease
  •  positive
  •  negative 

An examiner naturally develops a directional hypothesis from research questions and uses statistical techniques to make sure the validity of the hypothesis.

Directional hypotheses are also called one-tailed tests.

It is because the critical region is in one tail and the error is all in one direction (also less than or greater than a central position, not both).

A directional hypothesis expresses not only that a null hypothesis is false, but also that the definite value of the parameter we are concerned in is either greater than or less than the value specified in the null hypothesis.

Example of Directional Hypothesis: 

A directional hypothesis (or one-tailed hypothesis) expresses which technique you think the results are going to go, for instance in an experimental study we can say that the participants who have been lacked sleep for 24 hours will have more freezing symptoms in the subsequent week after contact to a virus than participants who have not been sleeping deprived, the hypothesis differentiates the two groups or conditions and states which one will have more or less, be quicker or slower, etc.

If we had a correlation study, the directional hypothesis would affirm whether we anticipate a positive or a negative correlation, we are expressing how the two variables will be linked to each other, e.g. there will be a positive correlation between the number of stressful life occasions experienced in the last year and the number of coughs and colds suffered, whereby the more life incidents you have suffered the more cough and cold you will have had. 

The directional hypothesis can also affirm a negative correlation, e.g. the higher the number of Facebook friends, the lower the life contentment score 

Importance of a Directional Hypothesis:

  • provides a direction to the research
  • helps in devising research techniques
  • indicates the focus of the researcher
  • avoids from blind research
  • makes sure accuracy and precision

Strong Point of a Directional Hypothesis:

Directional hypotheses are stronger than nondirectional hypotheses.

Their selected nature also formulates them more important: as the whole critical region is determined in one tail, data whose test statistic might fall in the region of negative response in a one-tailed test might go down the outer surface in a two-tailed test.

For that reason, they are a fine selection each time you are convinced, before analysis that the option of alteration is in only one direction.

Where there is any uncertainty, a two-tailed test must be used as an alternative.

FAQs about Directional Hypothesis 

Why should a hypothesis be directional?

Directional hypotheses are used when previous research suggests that the findings of a study will go in a particular direction; however, as the extract says ‘a psychologist was not aware of any previous research’, a directional hypothesis would not be appropriate. 

2. Why are directional hypotheses used?

A nondirectional hypothesis is used when a two-tailed test of significance is run, and a directional hypothesis when a one-tailed test of significance is run.

The reason for the different types of testing becomes apparent when examining a graph of a normalized curve.

3. Can the null hypothesis be directional?

A directional hypothesis states not only that a null hypothesis is false, but also that the actual value of the parameter we’re interested in is either greater than or less than the value given in the null hypothesis. 

4. When should a hypothesis be directional?

A directional hypothesis is a prediction made by a researcher regarding a positive or negative change, relationship, or difference between two variables of a population.

This prediction is typically based on past research, accepted theory, extensive experience, or literature on the topic.

5. What is the difference between directional and nondirectional hypothesis?

The directional hypothesis measures the direction of the variation of two variables.

This effect of one variable on the other variable can be in a positive direction or in a negative direction. 

The non-directional hypothesis does not indicate the kind of effects but only shows the relation between two variables.


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