Front

What are categorical variables?

Back

Categorical variables represent characteristics or qualities described in words, taking on values that are names or labels.

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What is a response variable?

Back

A response variable is a variable that responds to a change and measures the outcome of a study. It is also called the dependent variable or predicted variable.

Front

What is an explanatory variable?

Back

An explanatory variable is any factor that can influence or explain the response variable. It is often called the independent variable or predictor variable.

Front

How should categorical variables be displayed graphically?

Back

The explanatory (or independent) variable is best placed on the horizontal axis, and the response (or dependent) variable forms part of the legend.

Front

What is Pearson's correlation coefficient?

Back

Pearson's correlation coefficient, denoted by rxy or simply r, is a precise measure that calculates the strength of a relationship between variables.

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What should be considered when observing an association between two variables?

Back

One must not assume a causal relationship; the association could be due to coincidence or a lurking variable (confounding factor).

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How to interpret the y-intercept in a regression line?

Back

If the value of the explanatory variable is 0 units, the predicted value of the response variable is the y-intercept units.

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What is the line of regression?

Back

The line of regression, also known as the line of best fit or the least squares regression line, is determined by eye.

Front

How to interpret the slope in a regression line?

Back

For every increase of 1 unit in the explanatory variable, there is an average increase/decrease of gradient unit in the response variable.

Front

What is a lurking variable?

Back

A lurking variable is a hidden variable that affects the variables being studied, potentially leading to a false perception of a relationship between them.