Remember that any form of y = mx + c can be a straight line. Any of these values can also equate to 0!
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\nIn a positive correlation, as one variable increases, the other increases. This looks like a line of points going up and to the right. In a negative correlation, as one variable increases, the other decreases. This looks like a line of points going down and to the right. If there is no correlation, there is no relationship between the two variables. This looks like a lot of points scattered randomly.
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