When the road is not yet clear  to you,
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The adjusted multiple correlation coefficient is a correction of the multiple...

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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