Adjusted R-square

The adjusted multiple correlation coefficient is a correction of the multiple...

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Online dictionary research and statistics

Adjusted R-square

The adjusted multiple correlation coefficient is a correction of the multiple...

Analysing qualitative data.

Qualitative data can take various forms, but most often it is text. Use our...

Analysing quantitative data

Quantitative data has to be analysed with quantitative techniques. Although...

ANCOVA (Analyses of covariance)

ANCOVA is short for ANalysis of COVAriance. It is a statistical technique in...

ANOVA (Analyses of variance)

ANOVA is a statistical technique to determine whether the means of three or more...

Applied research

Applied research is an activity used to solve a problem. It has not the...

Average

This information can be viewed at the keyword Mean Return to the index of...

Bias

Bias is a distortion in receiving correct information. The term originates from...

Case study

A case study is a research with only one respondent, object or case. From this...

Chi square distribution

The chi-square distribution is the squared t-distribution. Because it is squared...

Chi square test

The chi-square test is used to find out whether a calculated value exceeds a...

Chi square test for frequency distributions

The chi-square test for frequency distributions is used to test wether an...

Chi square test for contingency tables

The chi-square test for contingency tables is used to find out whether the...

Chi square value

The chi-square value is the value at the base line of the chi-square...

Clinical Research Trial (CRT)

A clinical research trial (CRT) is a research in which an experimental design is...

Codebook

A codebook is a document in which the names and the values of the variables used...

Cohens Kappa

See Kappa Return to the index of this dictionary...

Collecting data

Although the term collecting data is used in many textbooks, the term gathering...

Comparative reserach (the design of)

In comparative research two or more groups or situations are compared with each...

Conceptual model

A conceptual model is a graphical representation of the aspects of a research...

Confidence interval

With a sample you can calculate the mean or a proportion of a variable. This...

Confounder

A confounder is a variable that influences the relationship between the...

Construct validity

Construct validity is raising and answering the question whether the aspects...

Content validity

Content validity is raising and answering the question whether the aspects that...

Control variable

A control variable is a variable that might influence the relationship between...

Correlation

Correlation is the measured strength of cohesion between two continuous...

Counterbalancing

When participants have to go through multiple conditions, collecting the data...

Covariable

A covariable is a variable that has a correlation or association with the...

Cramers V

Cramers V is the unit for the strength of cohesion between two variables...

Cronbach's alpha

Cronbach’s alpha is a unit for internal consistency, a form of...

Data analysis, plan for -

A data analysis plan is a necessary part of the research design that describes...

Degrees of Freedom

The Degrees of Freedom in statistical tests are indicative for the stability of...

Dependent variable

A dependent is the variable where the research is done for. It is the variable...

Design

Design is short for Research Design. Every research has a design. Six of them...

Descriptive research

In Descriptive Research a situation is described and the relations between the...

Desk research

Desk research is one of the four ways to collect data for research. With desk...

Dichotomy

A dichotomy is a nominal variable with only two values. A dichotomy is a...

Drop outs

A drop out is a deliberately deleted object or respondent by the researcher. To...

Dummy variable

A dummy is a nominal variable with the values 0 and 1. It can be seen as an...

Evaluation research (the design of)

Evaluation research is a research in which a situation is compared with a...

Evidence based practice

Evidence-based practice can be seen as 'practice shows that it works'...

Experimental research (the design of)

An experimental research design is a design in which the data of an experimental...

Experimental variables

Variables can be distinguished into experimental and non-experimental variables....

Explorative research (the design of)

In explorative research it is not necessary to have a thoroughly theory and...

External validity

External validity is raising and answering the question how well the results are...

F-distribution

The F-distribution is a ratio distribution and created by dividing two positive...

F-value

The F-values are at the bottom line of the probability density function of the...

Face validity

Face validity is a cumbersome statement about the meaning of a variable. When...

Factor analysis

Factor analysis is an arithmetic tool to see if a list of items has enough...

Field research

Field research is one of the four options where to gather the data for a...

Friedman test

The Friedman test is used for testing the difference between three or more...

Fundamental research

Fundamental research is a research that is conducted to test a theory that is...

Gathering data

Gathering data or collecting data is the filling of the database that a...

Generating data

Sometimes data are generated. That is the case when scientists conduct a...

Hierarchical regression

Hierarchical regression analysis is a technique that compares two regression...

Hypothesis

A hypothesis is a statement about an expected outcome of a research. A...

Independent variable

An independent variable is a variable that is being for making comparisons. ...

Informed consent

An informed consent is a signed document on which the respondent explicitly...

Internal consistency

Internal consistency is one of the four basic types of reliability. It examines...

Internal validity

Internal validity is raising and answering the question how well the exhibited...

Interobserver reliability

If the observations are recorded, the aspects of interest can be coded by two or...

Interval data

A variable is said to be measured at an interval scale when there are a lot of...

Interview (conducting interviews)

Interviewing is systematically gathering data from the empery by asking people...

Interviewer bias

One of the interviewer's duties is to ensure that you get reliable answers....

Kappa, Cohen's

Cohen's Kappa is a coefficient of agreement between two raters or - more...

Kendalls tau

Kendall’s tau is the unity for the strength of cohesion between two...

Kolmogorov-Smirnov test

The Kolmogorov-Smirnov test is a commonly used test to check whether a variable...

Kruskal-Wallis test

The Kruskal-Wallis test is used for comparing the scores of three groups on one...

Kurtosis

Kurtosis is an indicator for the flatness of a distribution A list of numbers...

Laboratory research

Data can be gathered in the field by observing or using a questionnaire or...

Likert scale

A Likert-scale is a question of which the answers are given on a scale with...

Longitudinal research

A Longitudinal Research Design is a design of a research on which a lot of...

Mann-Whitney test

The Mann-Whitney test is used for comparing the scores of two groups on one...

MANOVA (multivariate analyses of variance)

MANOVA stands for Multivariate ANalysis Of VAriance. With this statistical...

Matchen

Matching is adjusting respondents or objects to groups after measuring some...

Mean

The mean is the sum of all numbers in a list divided by the amount of numbers in...

Measuring, the five methods of -

Measuring is assigning values to the characteristics of people, animals,...

Measuring using instruments

Measuring with instruments is gathering data from the empery with instruments....

Median

The median is the value of the number in the centre of an ordered list of...

Mediation

Mediation is a theoretical issue in which other factors provide a better...

Mode

The mode is the most frequent answer given. Suppose you made a questionnaire...

Model

A model is a replica of the empery (the real world). Some models are an exact...

Moderation

Moderation is a theoretical issue assuming that a combination of aspects will...

Multicollinearity

Multicollinearity is due to a high correlation between two or more predictive...

Multilevel analysis

Multilevel analysis is analysing data that are collected from different levels,...

Multiple choice question

A multiple-choice question is characterised by the fact that only one answer can...

Multiple correlation

The multiple correlation coefficient is an extension of Pearson's product...

Multiple regression

Multiple regression analysis is a technique to derive a line that can predict an...

Multiple response question

A multiple response question is characterised by the fact that none, one or more...

Nominal data

Nominal data are used in statistics to identify groups. These variables are used...

Non-response

The people who do not respond on a call to participate in a research are called...

Non-response, reasons for -

There are many reasons for not participating in an investigation. If you know...

Non-response research

In non-response research the researcher tries to answer four questions: 1) Why...

Normal distribution

The normal distribution is the distribution of a variable in which most scores...

Objectivity

Objectivity is important because knowledge should be independent from the...

Observing (as a research technique)

Observing is systematically gathering data from the empery with the senses. The...

Operationalising

Variables are the outcomes of measurements. The way a variable is measured is...

Ordinal data

It is said that a variable is measured at the ordinal level if there is a...

Outlier

An outlier is an extreme answer or a respondent who gives extreme answers that...

p-value

The p-value is the chance-value and is always between 0 and 1, or in percentages...

Partial correlation

Partial correlation is by definition the unique correlation between two...

Placebo

A placebo is a treatment of people with an ineffective drug. In this way, the...

Phi-coefficient

The phi-coefficient is a value that indicates the strength of cohesion between...

Population

The population is the group of elements (people, animals, objects) that the...

Predictive validity

Predictive validity is raising and answering the question about how well the...

Problem statement

The problem statement can be seen as part of the research: without a problem...

Qualitative research

Qualitative research is a research with a few respondents, objects,...

Quantitative research

Quantitative research is a research with a lot of respondents, objects,...

Quantitative value

A number is a quantitative datum. A qualitative datum is any other type of data...

Questions, types of -

In surveys and interviews information is gathered by asking questions. Different...

Random, at -

At random is selecting people or objects and dividing them into groups without...

Range

The range is the difference between the minimum and maximum values in a list of...

Ratio data

A variable that is measured at a ratio scale has many values and has an absolute...

Regression analysis

Regression analysis is a technique to derive an equation to predict outcomes...

Reliability

Reliability is a statement about how reliable the information collected is. Four...

Replicapability

Replicability is a high valued aspect of any research. A research that is not...

Representativity

Representativity is to ensure that the results of a study apply to the total...

Research, definition of -

Research is an activity to answer questions for which first new data have to be...

Research design

A Research Design is a graphical overview of the groups taking part in the...

Research Question

The research question is the main question that has to be answered when the...

Response

The response is that part of the sample that contributed to the research by...

Sample / sampling

The sample is the group persons that are asked to participate in a study. The...

Scientific research

Scientific research is research that is done in accordance with the rules of...

Secondary data analysis

Secondary data analysis is the analysis of data from sources that were not...

Semantic differential

A semantic differential is a question with two opposites terms at both ends of a...

Shapiro-Wilk test

Like the Kolmogorov-Smirnov test, the Shapiro-Wilk test is a commonly used test...

Simulation

Simulation can be used as a type of research. The data are collected from a...

Skewness

Skewness is an indicator for how far the mean is from the centre of the...

Spearman rank correlation

The Spearman rank correlation is the measurement unit for the strength of...

Split half reliability

Split half reliability is a statement about how reliable the information...

Spurious effect

A spurious effect is an (statistically significant) effect between two variables...

Standard deviation

The standard deviation is an indicator for the dispersion in a list of the...

Survey

A survey is a type of research in which information is collected with a...

t-distribution

The t-distribution is a density distribution that looks similar to the standard...

t-test (groups)

A t-test groups is a test for comparing the means of two groups. There are...

t-test (one sample - )

A one sample t-test is a test for comparing the mean of a variable with a...

t-test (pairs)

A paired sample t-test is a test for comparing the means of two characteristics....

t-value

Four distributions are very commonly used in statistics: the normal...

Text analyses

See analysing qualitative data >>> Or download our manual How to...

Test for normality

In many statistical tests the assumption of normal distribution is made for...

Test-retest reliability

Test-retest reliability is a statement about how reliable the gathered...

Test-test reliability

Test-test reliability is a statement about the reliability of the information...

Theory

A theory is an idea about how the empery (the real world) is functioning. This...

Transferring data

Transferring data is simply copy paste the data from other sources. The theory...

Triangulation

Triangulation is verifying the information by comparing it with other sources. ...

Validity

Validity is a statement about the meaning of a variable or a construct. When...

Variable

A variable is a general name for attributes of objects. The value of a variable...

Variance

The variance is the square of the standard deviation . Therefore, look for...

VIF-value

VIF stands for Variance Inflation Factor. Values lower than 4 show that the...

Weighting

Weighting is a statistical technique to compute a general mean or a percentage...

Wilcoxon test

The Wilcoxon test is used for testing the difference between two attributes of...

z-value

Four distributions are very commonly used in statistics: the standard normal...

The biggest cause of a tough ongoing research is a bad research question.

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