Line Plots — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
On a Grade 3 line plot, each O mark stands for one piece of data.
Corrected: On a Grade 3 line plot, each X mark stands for one piece of data.
Line plots in Grade 3 use X marks, not O marks, to show how often a value appears.
2. Fix the sentence:
The most common value on a Grade 3 line plot is called the medium.
Corrected: The most common value on a Grade 3 line plot is called the mode.
In Grade 3, the value that appears most often on a line plot is called the mode.
3. Fix the sentence:
A Grade 3 line plot needs no number line under the X marks.
Corrected: A Grade 3 line plot needs a number line under the X marks.
Without a number line, the X marks on a Grade 3 line plot would not have a scale.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. On a Grade 3 line plot of siblings, 4 students have 2 siblings, so there are 4 X marks above 2.
Each student is shown with one X mark, so 4 students means 4 X marks above 2.
2. A Grade 3 line plot shows books read: 3, 3, 5, 5, 5, 7. The mode is 5.
The number 5 appears three times, more than any other value, so 5 is the mode.
3. Plant heights in cm on a Grade 3 line plot: 8, 8, 9, 10, 10, 10. The total number of plants is 6.
Add all the X marks: 2 + 1 + 3 = 6 plants total on the line plot.
4. On a Grade 3 line plot, 2 students have 0 siblings and 5 students have 1 sibling. There are 3 more students with 1 sibling than with 0.
5 minus 2 equals 3, so 3 more students have 1 sibling than 0 siblings.
Part C: True or False?
Read each statement. Circle True or False.
1. On a Grade 3 line plot, each X mark represents one data value.
True False
By definition, each X mark on a Grade 3 line plot stands for one piece of data.
2. On a Grade 3 line plot of plant heights, the tallest stack of X marks shows the least common height.
True False
The tallest stack of X marks shows the most common value, not the least common.
3. A Grade 3 line plot must have a number line as its scale.
True False
All line plots in Grade 3 use a number line scale to organize the X marks.