A scatter plot is a graph that shows the relationship between two quantitative variables. Each point represents an observation in the dataset.

A positive relationship indicates that as one variable increases, the other variable also tends to increase.

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

'No relationship' means that there is no discernible pattern or correlation between the two variables.

A line of best fit is a straight line that best represents the data on a scatter plot, showing the trend of the data.

Quadratic regression is a type of regression analysis used to model the relationship between a dependent variable and an independent variable using a quadratic equation.

The coefficient 'a' indicates the direction of the parabola: if 'a' is positive, the parabola opens upwards; if 'a' is negative, it opens downwards.

The vertex of a parabola is the highest or lowest point on the graph, depending on the direction it opens.

By observing the trend of the points: if they rise together, it's positive; if one rises while the other falls, it's negative; if there's no clear trend, it's no relationship.