How can you tell from a scatter plot whether 2 variables have a positive correlation a negative correlation or no correlation?

Suppose the scatter plot is of a variable X on the horizontal scale and Y on the vertical scale.

Find the approximate middle of the x values and call it p.

Find the approximate middle of the y values and call it q.

Draw horizontal and vertical lines through the point with coordinates (p, q).

If you know about quadrants, skip this paragraph. The two lines through the point (p,q) divide up the plane into 4 quadrants. Quadrant I is top right. Quadrant II is top left. Quadrant III is bottom left. Quadrant IV is bottom right.

If the scatter plot is mostly in quadrants I and III the correlation is positive. If mostly in quadrants II and IV the correlation is negative. Otherwise the correlation is small.

Remember, though, that 0 correlation does not mean no relation. y = x2 will have 0 correlation but it is a perfectly well defined relationship!

Suppose the scatter plot is of a variable X on the horizontal scale and Y on the vertical scale.

Find the approximate middle of the x values and call it p.

Find the approximate middle of the y values and call it q.

Draw horizontal and vertical lines through the point with coordinates (p, q).

If you know about quadrants, skip this paragraph. The two lines through the point (p,q) divide up the plane into 4 quadrants. Quadrant I is top right. Quadrant II is top left. Quadrant III is bottom left. Quadrant IV is bottom right.

If the scatter plot is mostly in quadrants I and III the correlation is positive. If mostly in quadrants II and IV the correlation is negative. Otherwise the correlation is small.

Remember, though, that 0 correlation does not mean no relation. y = x2 will have 0 correlation but it is a perfectly well defined relationship!

Suppose the scatter plot is of a variable X on the horizontal scale and Y on the vertical scale.

Find the approximate middle of the x values and call it p.

Find the approximate middle of the y values and call it q.

Draw horizontal and vertical lines through the point with coordinates (p, q).

If you know about quadrants, skip this paragraph. The two lines through the point (p,q) divide up the plane into 4 quadrants. Quadrant I is top right. Quadrant II is top left. Quadrant III is bottom left. Quadrant IV is bottom right.

If the scatter plot is mostly in quadrants I and III the correlation is positive. If mostly in quadrants II and IV the correlation is negative. Otherwise the correlation is small.

Remember, though, that 0 correlation does not mean no relation. y = x2 will have 0 correlation but it is a perfectly well defined relationship!

Suppose the scatter plot is of a variable X on the horizontal scale and Y on the vertical scale.

Find the approximate middle of the x values and call it p.

Find the approximate middle of the y values and call it q.

Draw horizontal and vertical lines through the point with coordinates (p, q).

If you know about quadrants, skip this paragraph. The two lines through the point (p,q) divide up the plane into 4 quadrants. Quadrant I is top right. Quadrant II is top left. Quadrant III is bottom left. Quadrant IV is bottom right.

If the scatter plot is mostly in quadrants I and III the correlation is positive. If mostly in quadrants II and IV the correlation is negative. Otherwise the correlation is small.

Remember, though, that 0 correlation does not mean no relation. y = x2 will have 0 correlation but it is a perfectly well defined relationship!