Scatterplots

Front

What is a scatterplot?

Back

A scatterplot is a graph that shows the relationship between two quantitative variables by displaying data points on a two-dimensional axis.

Front

What does a positive correlation in a scatterplot indicate?

Back

A positive correlation indicates that as one variable increases, the other variable also increases.

Front

What does a negative correlation in a scatterplot indicate?

Back

A negative correlation indicates that as one variable increases, the other variable decreases.

Front

What does no correlation mean in a scatterplot?

Back

No correlation means there is no discernible relationship between the two variables; changes in one do not affect the other.

Front

How do you identify a linear association in a scatterplot?

Back

A linear association is identified when the data points form a pattern that can be approximated by a straight line.

Front

What is the purpose of a trend line in a scatterplot?

Back

A trend line is used to summarize the relationship between the variables and to predict future values.

Front

What is the difference between correlation and causation?

Back

Correlation indicates a relationship between two variables, while causation indicates that one variable directly affects the other.

Front

How can outliers affect a scatterplot?

Back

Outliers can skew the interpretation of the data, affecting the correlation and the trend line.

Front

What is the formula for calculating the correlation coefficient (r)?

Back

The correlation coefficient (r) is calculated using the formula: r = (nΣxy - ΣxΣy) / √[(nΣx² - (Σx)²)(nΣy² - (Σy)²)], where n is the number of data points.

Front

What does a correlation coefficient of 1 indicate?

Back

A correlation coefficient of 1 indicates a perfect positive linear relationship between the two variables.