Construct scatter plots

Detailed Explanation: Construct scatter plots

A scatter plot shows how two numerical variables are related. Each data pair becomes one point $((x,y))$:

• The $x$-variable goes on the horizontal axis.
• The $y$-variable goes on the vertical axis.
• Keep the two values from each pair together.
• Do not connect the points with line segments.

Example

A teacher records how many hours five students studied and their quiz scores.

Step 1: Identify the variables

• $(x=)$ hours studied, measured in hours
• $(y=)$ quiz score, measured in percent

The quiz score is paired with the number of hours for the same student.

Step 2: Choose and label the axes

Label the horizontal axis Hours studied (hours).
Label the vertical axis Quiz score (%).

Choose scales that include every value:

• Horizontal axis: $0$ to $5$, counting by $1$
• Vertical axis: $(50)$ to $(90)$, counting by $(10)$

The scales should be evenly spaced.

Step 3: Plot each ordered pair

Convert each row into an ordered pair:

For example, to plot $((3,65))$:

1. Start at $3$ on the horizontal axis.
2. Move up to $(65)$ on the vertical axis.
3. Place a dot there.

Repeat this for all five pairs.

Step 4: Check the scatter plot

Make sure:

• Every pair has exactly one point.
• The axes have labels and units.
• The scale is even and includes all the data.
• The points are not connected.

The points generally rise from left to right, suggesting that students who studied more hours tended to have higher quiz scores. This is an informal description of the pattern; no line or equation is needed yet.