Scatterplots & Trend Lines

Front

What is a scatterplot?

Back

A scatterplot is a graph that displays values for typically two variables for a set of data. Each point represents an observation in the dataset.

Front

What does a negative relationship in a scatterplot indicate?

Back

A negative relationship indicates that as one variable increases, the other variable tends to decrease.

Front

What is a positive correlation?

Back

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

Front

What is a negative correlation?

Back

A negative correlation means 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 apparent relationship between the two variables; changes in one do not predict changes in the other.

Front

What is the equation of a trend line?

Back

The equation of a trend line is typically expressed in the form y = mx + b, where m is the slope and b is the y-intercept.

Front

How do you find the slope (m) of a trend line?

Back

The slope (m) is calculated by taking the change in the y-values divided by the change in the x-values between two points on the line.

Front

What does the y-intercept (b) represent in a trend line equation?

Back

The y-intercept (b) represents the value of y when x is 0; it is where the line crosses the y-axis.

Front

What is the significance of the slope in a trend line?

Back

The slope indicates the direction and steepness of the line; a positive slope indicates a positive correlation, while a negative slope indicates a negative correlation.

Front

How can you determine the type of association from a scatterplot?

Back

You can determine the type of association by observing the direction of the points: upward for positive, downward for negative, or scattered for no association.