Mathematics
Grade 7
15 min
Create line graphs
Create line graphs
Tutorial Preview
1
Introduction & Learning Objectives
Learning Objectives
Identify the key components of a line graph (axes, labels, title, scale, data points).
Choose appropriate and consistent scales for both the x and y axes.
Accurately plot data points on a coordinate plane.
Connect plotted points with straight line segments to form a complete line graph.
Add a clear and descriptive title and axis labels to a line graph.
Interpret basic trends and changes shown in a line graph.
Ever wonder how meteorologists show temperature changes over a day? 🌡️ Or how stock prices fluctuate over time? Line graphs are key!
In this lesson, you'll learn how to construct line graphs from given data. Line graphs are powerful tools for visualizing how data changes over time or across another continuous variable, helping us spot trends an...
2
Key Concepts & Vocabulary
TermDefinitionExample
Line GraphA graph that uses points connected by line segments to show how a quantity changes over time or another continuous variable.A line graph showing how the number of visitors to a park changes each hour throughout the day.
X-axis (Horizontal Axis)The horizontal line on a graph, typically representing the independent variable (the variable that causes change, often time).On a graph showing temperature over a day, the x-axis would represent 'Time (hours)'.
Y-axis (Vertical Axis)The vertical line on a graph, typically representing the dependent variable (the quantity being measured or observed).On a graph showing temperature over a day, the y-axis would represent 'Temperature (°C)'.
ScaleThe range of values represented by each unit or interval...
3
Core Formulas
Axis Labeling Rule
X-axis: Independent Variable (Units)
Y-axis: Dependent Variable (Units)
Always label both the x-axis and y-axis clearly, including the units of measurement. The independent variable (what changes or is controlled, often time) goes on the x-axis, and the dependent variable (what is measured) goes on the y-axis.
Consistent Scaling Rule
Δx = constant and Δy = constant
Choose an appropriate and consistent scale for both axes. This means that the distance between any two consecutive tick marks on an axis must represent the same amount. The scale should accommodate the minimum and maximum values of your data and make the graph easy to read.
Plotting and Connecting Rule
Plot (x₁, y₁), (x₂, y₂), ..., (xₙ, yₙ) then Connect (xᵢ, yᵢ) to (xᵢ₊₁, yᵢ₊₁) with straig...
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Challenging
You are graphing the number of students in the cafeteria every 10 minutes, with data ranging from 15 students to 185 students. Which y-axis scale is the MOST effective for clearly showing the fluctuations in the data?
A.scale from 0 to 200 with intervals of 50.
B.scale from 0 to 200 with intervals of 25.
C.scale from 0 to 500 with intervals of 100.
D.scale from 0 to 1000 with intervals of 200.
Challenging
Two line graphs show the same company's profit data, which ranges from $1000 to $1200 over 6 months. Graph A's y-axis runs from $0 to $5000. Graph B's y-axis runs from $900 to $1300. How will the appearance of the line differ between the two graphs?
A.The line in Graph A will appear much steeper than in Graph B.
B.The line in Graph B will appear much steeper than in Graph A.
C.The lines will look identical in shape and steepness.
D.Graph A's line will be a straight line, while Graph B's will be curved.
Challenging
A line graph is created to show a town's population recorded every 10 years (1990, 2000, 2010, 2020). What is a key assumption a person makes when looking at the straight line segment connecting the point for 2000 and 2010?
A.The population did not change at all between 2000 and 2010.
B.The population changed at a constant, steady rate during that 10-year period.
C.The population in 2005 was exactly halfway between the 2000 and 2010 values.
D.The data for the years in between is missing and cannot be estimated.
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