A line plot (also called a dot plot) displays data along a number line, with an X or dot above each value for each occurrence. In fourth grade, line plots frequently use fractional measurements (lengths measured to the nearest 1/4 or 1/2 inch), connecting data analysis to fraction understanding. Students learn to create line plots from raw data, read information from existing plots, and answer questions about the data: "What is the most common measurement?" "How many items are longer than 3/4 inch?" "What is the difference between the longest and shortest?"
Collect real measurement data: measure objects to the nearest 1/4 inch and record on a class line plot. Start by interpreting pre-made plots before creating their own. Practice answering "how many more" and "how many in all" questions. Use line plots to motivate adding and subtracting fractions in context.
A line plot is the simplest way to see the shape of a data set at a glance. You draw a number line, then place an X (or dot) above a number every time that value appears in your data. Stack multiple X's if a value repeats. When you're done, taller stacks show more frequent values and you can instantly spot where most of the data clusters.
In fourth grade, line plots often use fractional measurements. Imagine measuring the lengths of pencils in your class to the nearest 1/4 inch and getting values like 4 1/4, 4 1/2, 5, 5 1/4, 5 1/4, and 5 3/4. You'd draw a number line from 4 to 6, marking every 1/4-inch interval, then place an X above each measurement. The two X's stacked above 5 1/4 tell you that length appeared twice — it's the most common, or mode. This visual connects directly to your work with fractions: you need to understand fraction values to space the number line correctly and place X's accurately.
Once the plot is built, you can answer questions about the data without sorting through a list. "How many pencils are longer than 5 inches?" Count the X's above every value greater than 5. "What is the difference between the longest and shortest?" Subtract the leftmost value from the rightmost — that's the range. "How many pencils were measured in all?" Count every X on the entire plot.
One important distinction: a line plot is not the same as a line graph. A line graph connects points with a line to show how something changes over time (temperature across a week, plant growth over days). A line plot shows the distribution of a single set of measurements — there is no time involved, and the X's are never connected. Mixing them up is one of the most common errors in data analysis, so always check: am I showing change over time (line graph) or the spread of a set of values (line plot)?