Research Methods
Lesson 1
Introduction to Aims & Hypotheses Investigation & Design Produced by
Aims
Hypotheses
Experimental / Alternative
One Tailed / Directional
Null
Two Tailed / Non-directional
Introduction A researcher in psychology will usually design their experiment or research by following these steps. Thinking about their aim. This will be followed by thinking about the possible hypotheses and there are at least two hypotheses for every investigation and these are the experimental / alternative hypothesis and the null hypothesis. The experimental / alternative hypothesis can be one tailed /directional or two tailed / non – directional.
Definitions:  Aim: an aim of an experiment can be defined as being the intended purpose of an investigation be it a theoretical or empirical investigation.  Hypothesis: a hypothesis can be defined as being a specific prediction made about the outcomes of an experiment by the researcher or investigator. There are at least two types of hypotheses in an experiment the experimental / alternative and the null hypothesis
• Experimental / alternative hypothesis: the experimental hypothesis sometimes referred to as the alternative hypothesis, predicts the possible outcomes of an experiment. The hypothesis can be one tailed / directional or two tailed / non – directional. • One tailed / directional: can be defined as being a hypothesis that predicts the direction of the outcome of an experiment.
Important note: see note on next slide for a more in-depth understanding of one tailed and directional hypothesis.
Note on one tailed / directional hypothesis. ďƒź In an experiment there are usually at least two groups of people participating in an experiment. An experimental group and a control group. Everything about the these two groups are as similar as possible except for one variable that is manipulated and that variable is the independent variable. ďƒź A one tailed hypothesis will usually predict which group (experimental or control) will perform better or worse in an experiment. Therefore it is referred to as the directional / one tailed hypothesis as it predicts which group will perform better or worse in a task of an experiment.
• Two tailed / non – directional: predicts that there will be a difference in performance in a task of an experiment between the two groups (control / experimental) participating. However, it does not predict which group will perform better or worse.
Important note: see note on the next slide for a more indepth understanding of two tailed / non-directional hypothesis.
Note on two tailed / non directional hypothesis In some cases a researcher may not be able to predict which group (experimental / control) will perform better or worse on a task in an experiment. In this case the investigator or researcher has the option of using a two tailed or non-directional hypotheses. The two tailed / non directional hypothesis predicts that there will be a difference in performance between the two groups but does not predict which group will perform better or worse. Therefore it is referred to as a non-directional / two tailed hypothesis as it does not predict which group will perform better or worse in a task of an experiment.
• Null hypothesis: the null hypothesis predicts that there will be no difference in the performance between the two groups (experimental / control). Further, if there is a difference the difference is only due to chance and not significant.
ďƒ˜ Important note: see note on next slide for a more in-depth understanding about experimental / alternative hypothesis and null hypothesis on the next slide.
Note on experimental / alternative and null hypothesis Let’s just say hypothetically that a researcher has put together an aim, an experimental / alternative hypothesis that could be one tailed / directional or a two tailed / nondirectional and a null hypothesis. The researcher will then perform the experiment or investigation, collate the data from the participants and use statistical test to see whether there is a difference between the experimental and control group. If there is a difference you will accept the experimental / alternative hypothesis and reject the null hypothesis. However, if there is no difference between the experimental and control group, the researcher will reject the experimental / alternative hypothesis and accept the null hypothesis.
Example: • Let’s just say hypothetically a researcher wants to investigate whether traditional teaching / learning methods are any different from virtual and independent learning. • By traditional teaching / learning we mean lectures in a hall or teachers teaching, and students learning in a classroom where there is a presence of a group of people. • By virtual and independent learning we mean learning on your own through distance learning using ICT – this is using the internet and satellite technology available for phones and computers as such.
• The researcher will do a lot of background reading on the both the benefits and disadvantages of these two approaches to teaching and learning. • The next step will be about reviewing some of the research already carried out on comparing these two approaches of teaching and learning. The purpose of this is to assist the investigator in making a decision whether to choose a directional or non-directional hypothesis and gain some ideas on designing their own experiment. • Once they have done the above they will put together an aim, experimental / alternative and null hypothesis for their experiment.
• The aim of the experiment should be unbiased or neutral. In our hypothetical example the aim could read something like this below: ďƒ˜ Comparing traditional teaching and learning to independent and virtual learning methods in education performance.
• The experimental or alternative hypothesis could be one tailed / directional or two tailed non-directional. If the researcher is replicating some other investigators study the chances are that the experimental / alternative hypothesis will be one tailed as the hypothesis will based on the evidence of previous research. • Always remember the experimental / alternative hypothesis can be written in one of two ways. See below: Traditional learners perform better in education compared to independent virtual learners.
or Traditional learners perform worse in education compared to independent virtual learners.
• However, say there is very little background literature evidence and the research available is inconclusive, or you as an investigator are probably the very first that is investigating a topic, the experimental / alternative hypothesis will usually be two tailed /non-directional. • In our hypothetical example the two tailed hypothesis could read something like the statement below: ďƒ˜ There will be a significant difference in education performance between traditional learners and independent virtual learners.
• As usual the null hypothesis predicts no difference. In our hypothetical example the null hypothesis will read something like the statement below: ďƒ˜ There will be no significant difference in education performance between traditional learners and independent virtual learners.
• Once the researcher has carried out the investigation and processes the data from the experiment. He / she will decide whether to do one of the following: Accept the experimental / alternative hypothesis and reject the null hypothesis of their experiment.
or Accept the null hypothesis and reject the experimental /alternative of their experiment. • This choice totally depends on the outcome of the results from the experiment.
Further Reading: • www.psychologyrevise.com Investigation & Design Hypotheses.
Research Methods Aims
• Wider reading – more practical examples and a quiz to test your knowledge on aims and hypothesis.