Methods glossary Flashcards
<p>Alpha value</p>
<p>Usually, the probability value
of .05 is the alpha value used in inferential statistics as the measure of significance. This value has been adopted as the threshold for accepting the null hypothesis (test result is greater than .05), or rejecting it (test result is equal to or less than .05).</p>
<p>Bar graph</p>
<p>A graph often used to visually compare differences between the means of separate groups or conditions. The x-axis represents the different groups and the y-axis represents the means. Each mean is drawn as a vertical bar, and because the means are from different categories (groups or conditions) the bars are not joined.</p>
<p>Baseline measure</p>
<p>The effect of the control condition on the dependent variable against which the effect of the experimental condition can be compared to give the
size of the difference between the two conditions.</p>
<p>Behavioural data</p>
<p>Data produced from measuring behaviour. These can cover a wide range of activities such as reaction times (e.g. time taken to press a buzzer) and memory (e.g. number of words correctly recognised) as well as less well-defined behaviours such as problem solving which might be described qualitatively.</p>
<p>Between-participants design</p>
<p>An experimental design where different participants complete each condition, so more participants are needed than for a within-participants design. Also known as independent groups design, independent
samples design, or independent measures design. Can help eliminate confounding variables such as demand characteristics since participants’ understanding of the whole experiment is restricted, but does not reduce the influence of individual differences.
</p>
<p>Bimodal distribution</p>
<p>A distribution with two modes. The distribution is described by two symmetrical bell-shaped curves that appear joined, with two peaks representing two values for the mode.</p>
<p>Categorical data</p>
<p>Data that have been classified into discrete categories which are measured at the nominal level. Numbers are often used as labels (e.g. male = 1, female = 2), but the order numerically is of no importance.</p>
<p>
| Categorical variable</p>
<p>A variable which is measured at the nominal level; data produced are grouped into mutually exclusive and distinct categories.</p>
<p>Cause and effect</p>
<p>The aim of any experiment, a general law which can be established when an isolated, independent variable is manipulated to cause a measurable effect on the dependent variable.</p>
<p>Chi-square test</p>
<p>A statistical test used to analyse data measured at nominal level. This test allows one to look for associations between two categorical variables, by comparing the observed frequencies against
the expected frequencies (see contingency 2
table). The test calculates the statistic c and Cramer’s V provides a measure of effect size.</p>
<p>Coding</p>
<p>The process of assigning or converting material to a code for the purpose of identification, classification or analysis.</p>
<p>Complete observer</p>
<p>A researcher who openly observes but does not participate in the research setting.</p>
<p>Condition</p>
<p>In an experiment, the different forms of the independent variable created from its being manipulated. Very often an experimental condition and a control condition are set up, so that the effects of each can be measured and compared, with the control condition giving a baseline measure.</p>
<p>Conditional Probability</p>
<p>The likelihood of something happening that is dependent on something else.</p>
<p>Confidence interval</p>
<p>The range of values within which a population mean is likely to fall. Confidence intervals are specified by stating the lower and upper bounds of the range. For normally distributed data, we can be 95 per cent certain that the population mean will fall within 1.96 standard deviation points of a sample mean. This allows us to judge whether two samples are from the same population where any difference between them is simply due to sampling error.</p>
<p>Confounding variable</p>
<p>A variable, which is not the independent variable, that affects the dependent variable in one condition more than another – hence confounding the results. Researchers strive to eliminate confounding variables through good experimental design.</p>
<p>Content analysis</p>
<p>A quantitative method of analysing data. For example, data from an interview will be analysed by counting the prevalence and sequence of certain words
and these are sometimes analysed using a chi-square test.</p>
<p>Contingency table</p>
<p>Table used in studies looking for an association between independent (mutually exclusive) categorical variables. The table presents the number of observations in each possible combination, or contingency, of each category. If there are two variables (gender; film preference) each with two categories (male/female; horror/romance), then the number of observations in each possible combination of categories would be presented in a 2 x 2 contingency table.</p>
<p>
| Continuous variable</p>
<p>A variable that can produce data of any value (including decimal places) between the highest and lowest points on a scale; e.g. time taken to recall items in a memory test.</p>
<p>Control condition</p>
<p>The condition of the independent variable which is in all respects but one identical to the experimental condition – nothing is introduced to cause the dependent variable to change. The control condition can then be used to give a baseline measure.</p>
<p>Controls</p>
<p>Techniques used in an experiment to eliminate the foreseeable effects of any confounding variables.</p>
<p>Conversation analysis (CA)</p>
<p>An analytic method which focuses on the precise details of conversational interactions and on how people talk – for example the orderliness, structure and sequential patterns of interaction.</p>
<p>Correlation</p>
<p>The relationship, or association, between two variables whereby if the value of one changes so does the value of the other. One variable cannot be said to cause the other to change.</p>
Correlation coefficient
A numerical measure between -1 and +1 where the size of the number indicates the strength of the relationship between the two variables in a correlation, or the effect size. A value of 1 shows a perfect positive correlation while a value of -1 shows a perfect negative correlation. If the correlation coefficient is 0, there is no relationship between the two variables at all.
Counterbalancing
A control introduced to eliminate practise effects as a confounding variable in a within-participants experiment, whereby different participants undergo the conditions in a different order from one another.
Cramer’s V
A measure of effect size reported when using the chi-square test.
Data
Information collected during a study that has been documented in a suitable manner ready for communication or analysis.
Debriefing
The procedure where participants are given previously undisclosed information about a research project following completion of their participation.
Degrees of freedom (df)
A concept often defined as the number of scores whose values are free to vary. Degrees of freedom take account of the size of a sample, the number of variables, and the number of conditions in a study, and are reported with most inferential statistics.
Demand characteristics
Potentially a confounding variable. Introduced when participants do not respond naturally in an experiment, but react as they think they are expected to. The influence of demand characteristics may be reduced by using a
between-participants design, as participants take part in only one condition.
Dependent variable (DV)
The variable that is measured in an experiment, whose values result from manipulating the independent variable.
Descriptive statistics
A set of statistics used to summarise and present numerical data (e.g. mean and standard deviation).
Discourse analysis
Focuses on the ways in which people make meaning – discourse is unravelled in microscopic ways to see what it consists of and how it is put together to accomplish different actions.
Discrete variable
A variable that can produce data of only certain values, such as only whole numbers, between the highest and lowest points on a scale; e.g. the number of items recalled in a memory test can only be measured in whole numbers.
Double-blind testing
In drug trials particularly, the process of not informing either the participants or the drug administrator whether they are dealing with the real drug or not, to avoid confounding variables such as demand characteristics.
Ecological validity
The extent to which a study reflects naturally occurring or everyday situations. Ecological validity is often low in laboratory experiments where control of confounding variables is, however, higher.
Effect size
The magnitude of the effect the independent variable has on the dependent variable or the size of the relationship between two variables. In experimental designs, the statistic d is a standardised measure of effect size, calculated by subtracting one sample mean from the otherand dividing the result by the mean standard deviation. A correlation coefficient is also a measure of effect size, as is Cramer’s V which is a measure of effect size for a chi-square test.
Empirical evidence
Evidence based on some form of experience such as that gained through experimentation, observation, surveying or interviewing.
Epistemology
Epistemology is the ‘theory of knowledge’. It refers to the principles of what can be known and how we can know it; that is, how we can find out about it.
Error bar chart
A graph used to present confidence intervals. The upper and lower bounds of the confidence interval are represented by single lines above and below the mean, which is drawn as a single point.
Evidence
Information presented to determine or demonstrate the truth or the plausibility of an assertion, a consequence of the way that information is gathered, documented and analysed. Anecdotal evidence is informal argument based on personal experience or hearsay. In quantitative research, scientific evidence serves to either support or
counter the truth and validity of a hypothesis and is established through empirical analysis such as statistics. In hermeneutic research, evidence means drawing plausible inferences from patterns of meaning implied in the data.
Experiment
A research method used to investigate a hypothesis about the effect of the independent variable on the dependent variable. As far as possible the experimenter attempts to control for any other variables that might influence the dependent variable.
Experimental condition
A form of the independent variable created from its being manipulated. Unlike control conditions, something is introduced to the experimental condition as the possible cause of change in the dependent variable.
Experimental design
See ‘between- participants design’ and ‘within-participants design’.
Experimenter effects
Potentially, a confounding variable. Introduced by the experimenter or researcher exerting an influence, consciously or unconsciously, reducing objectivity. Experimenter effects can be overcome by ensuring all participants are treated in the same way as each other (e.g. each participant is read the same instructions), and by limiting experimenter contact with them as far as possible.
Fatigue effects
Introduced when a study takes a long time to run and participants become tired. Fatigue can affect responses as the study progresses, particularly if the participants are young children or elderly people. Fatigue effects can sometimes be limited in experiments by using a between- participants design, so no individual participant is required to complete the whole experiment.
First-order coding
The organising and categorising of data in a transcript by capturing chunks of meaning and giving them codes or labels. The process is purely descriptive, with minimal interpretation.
Fisher’s exact probability test
A statistical test used instead of the chi-square test when an expected frequency of less than 5 occurs in more than 25% of the cells of a 2 6 2 contingency table.
Generalisability
The extent to which research findings may be applied to a larger population and/or other situations.
Generalisation
To establish general laws or statements which apply across participants and specified conditions.
Habituation
Introduced when the same stimulus or task is presented to the same participants many times. Participants become increasingly used to responding to the stimulus or performing the task, which may obscure the effects of the independent variable. Habituation can sometimes be limited by using a between-participants design, or by simply reducing the number of responses required of participants.
Hermeneutic
The theory and practice of interpretation, involving the analysis of meanings in subjective accounts.
Histogram
A graph showing the number of occurrences, or frequency, of each value in a data set across the range (hence also known as a frequency distribution). The y-axis represents frequency and the x-axis represents the data range. Each value is drawn as a vertical bar and, because data are continuous, the bars are joined together.
Hypothesis
A statement making a prediction about the results of a study.
Independent samples t-test
A parametric test of difference used in inferential statistics to analyse data produced by an experiment with a between-participants design and which has two conditions. This test may also be called the unrelated t-test, independent t-test or between-groups t-test.
Independent variable (IV)
The variable that is manipulated in an experiment, to
investigate a potential effect on the dependent variable that is measured.
Individual differences
Introduced when, for example, different participants are allocated to different conditions in an experiment, so that the naturally occurring variations between people may obscure the effects of the independent variable. The influence of individual differences may be reduced by firstly ensuring the sample is large enough, by randomly allocating participants to each condition, and/or by using a within- participants design.
Inferential statistics
These involve statistical tests which allow conclusions to be drawn from numerical data generated by research. The tests calculate a statistic, from which a probability value can be derived telling us the likelihood of any difference of relationship being due to sampling error.Informed consent
Informed consent
The permission granted by a participant after he or she has received comprehensive information about the study.
Inner experiences
The private monologues (thoughts), feelings, sensations and process experienced by individuals either at a conscious or unconscious level.
Insider viewpoint
A viewpoint gained from introspection, interviews and analyses, where the researcher tries to see and think about the data through the eyes of the participant generating the data.
Interpretation
A representation of the meaning or significance of something.
Interpretative repertoires
A term associated with discourse analysis. Interpretative repertoires are ‘turns of phrase’ or arguments that people typically employ to describe or explain things. These are systematically related sets of terms that are commonly used in society because they are developed from particular historical contexts and have become part of the common sense of a culture or a particular institution. They are often organised around metaphors. This means that interpretative repertoires are a way of picking out the familiar arguments that tell us something about how a society, community or social group make sense of social life. In other words, they allow us to identify the taken-for-granted cultural resources found in talk.