Correlation
If a graph shows many points tightly clustered going upward, what kind of correlation is it?
Strong Positive Correlation
In y=4x−7y = 4x - 7y=4x−7, what does the -7 represent?
Y-Intercept
A student notices that as screen time increases, sleep decreases. What type of correlation is this and why?
Negative Correlation
A line of best fit shows a pattern going down. If x increases, what happens to y?
Y decreases.
What is the coordinate called where a line crosses the y-axis?
y-intercept
If a graph shows many points spread out across a graph going down what kind of correlation is it?
Weak Negative Correlation
A line has a slope of 3/2. What does this mean?
Y increases 3 units for every 2 units x increases.
Why might height and shoe size show a correlation but not a perfect one?
Other factors can affect shoe size.
A line of best fit shows a pattern going up. If x gets bigger, what happens to y?
Y also gets bigger.
Which line has the greater slope:
y=2x+1y or y=5x−3y
y=5x−3y
A scatter plot looks like a cloud with no pattern.
No Correlation
Rewrite in slope-intercept form:
2y=6x+8.
y=3x+4
A graph shows data that increases, but not in a straight line. Can you still use a line of best fit?
Yes
If a line of best fit is used on data, what kind of values does it help you find? Known or Unknown?
Unknown values
A line goes through the points (1, 3) and (3, 7). What is the slope?
2
A graph has a line that goes perfectly through all points upward.
Perfect Positive Correlation
A line goes through (0, 5) and (2, 9). What is the slope?
2
Two variables show a weak correlation. What does that mean about predictions? Are they more or less reliable?
Less Reliable
What do you look at first before making a prediction from a graph? The Pattern Or Line?
Pattern
If the slope of a line is negative, which direction does the line move
left to right
If most points are close to the line of best fit, what does that mean?
Strong Relationship/Correlation
A line has a negative slope and a positive y-intercept. What does the line look like? Show us on a graph on your whiteboard or in words.
A line that starts above 0 and goes downward from left to right.
Why is correlation NOT the same as cause?
Correlation means they are related, but one does not necessarily cause the other.
If the points on a graph are very spread out, what should you say about predictions?
They are less reliable
True or False: A line of best fit must pass through every point on the graph.
false