Tag Archives: Two quantitative variables

Hypothesis Test for Paired Means

This test is sometimes called a Matched Pairs Hypothesis t Test. Matched pair design is when a person is tested against himself or very similar subjects matched in pairs. The randomness happens in which treatment is given first (if the subject is paired with himself) or which treatment is given to who (if contrasting the […]

Confidence Interval for Paired Means

The method of paired means is used when two sets of data have the same number of elements, and there exists a one-to-one correspondence between the elements of each set. The first step in using this method is to calculate the difference between the two sets of data: . This results in one quantitative variable […]

Least-Squares Regression Line

The least squares regression line is a “line of best fit” used in scatter plots to predict where data is likely to fall in the range of response data.  The formula for this regression line is ŷ=b0 +b1x (Where ŷ is the predicted value, b0 is the intercept, and b1 is the slope of the […]

Least-Squares Regression Line

A least-squares regression line is used to assess the relationship between two quantitative variables. It is used to estimate the value of the response variable given an arbitrary value of the explanatory variable. There are four requirements that must be satisfied before a valid least-squares regression line can be calculated: The two variables are quantitative. A […]

Pearson Correlation Coefficient (r)

The Pearson Correlation Coefficient is a measurement of correlation between two quantitative variables, giving a value between -1 and 1 inclusive. This correlation demonstrates the degree to which the variables are dependent on one another. In other words, if the value of r is 1 or -1, then that means that all of the data points lie […]


A scatter plot is a graph representing the relationship between two quantitative variables. Each data point is represented by a dot on a cartesian plane with its position determined by its value of the two variables. For example, if I were to create a scatter plot using the variables of height and weight, the position of […]


A scatter plot is a graph used to visually examine the relationship between two quantitative variables that are plotted on the x- and y- axis, respectively. Points are plotted in relation to both variables, and from this a correlation can be determined.  A “line of best fit” can be used further in analysis of the […]