Before you can read line graphs and scatter plots, you must own every piece of vocabulary the parent note (parent topic) quietly assumes. Let's build each one from nothing, in an order where every idea leans on the one before it.
The picture (figure below): a horizontal ruler with 0 marked in orange in the middle. The magenta arrow points right and is labelled bigger; the violet arrow points left, labelled smaller. The single insight to carry away: a number's value is just where it sits on this road — nothing more.
Why the topic needs it: every axis of every graph is a number line. If you can find 28 on a ruler, you can find "28°C" on a temperature axis.
The word ordered matters: (3,70) and (70,3) are different dots. The first number is always the across-value, the second always the up-value.
How to read the figure below: the magenta arrow shows the first move (4 steps right along x); the violet arrow shows the second move (5 steps up along y); the orange dot where they finish is the point (4,5). Key insight: a point is two moves from the origin, always across first, then up.
Why the topic needs it: the parent note writes things like (3,70) meaning "studied 3 hours, scored 70". Every dot on a scatter plot and every marked point on a line graph is one ordered pair.
Once the two axes cross, they chop the sheet into four regions, called quadrants. Which region a point lands in is decided entirely by the signs (plus or minus) of its two coordinates.
How to read the figure below: each quadrant is tinted and labelled with its sign pair, and a sample dot sits in each so you can see left/right is governed by the sign of x and up/down by the sign of y. Points on an axis (one coordinate is 0) belong to no quadrant — the origin (0,0) sits on the fence between all four.
Before quoting the famous formula, let's earn it — see why every non-vertical straight line has this exact shape.
How to read the figure below: the magenta line is y=mx+c; the orange dot on the y-axis marks c (where the line starts); the violet steps show one Δx across producing Δy up — their ratio ism. Insight: c = where it starts, m = how fast it rises.
Why the topic needs it: the "line of best fit" through a scatter plot is exactly such a line. If m=2 in "hours vs score", each extra hour is worth +2 points on average. You meet this formally in 2.4.01-Linear-equations and 3.2.01-Functions-and-graphs.
How to read the figure below: the violet dots form a cloud leaning upward, and the magenta arrow traces that lean — that upward lean is positive correlation. The lone orange dot floating high above the cloud is the outlier. Insight: correlation is the lean of the crowd; an outlier is a dot that ignores the crowd.
The flow chart below is a dependency map: read an arrow A→B as "you need A before B makes sense." Start at the top (Number line) and follow the arrows down — every box only appears once everything feeding into it is already understood. Two streams (left = line graphs, right = scatter plots) both flow into the final box, interpret the story, which is the whole point of the topic. Use it to spot which earlier box to revisit if a later idea feels shaky.
