A student measures 8 pencils and records these lengths in inches: 4, 5, 5, 6, 4, 5, 6, 5. She makes a line plot. Above which number will the tallest column of X marks appear?
A4 — it appears first on the number line
B5 — it appears most often in the data
C6 — it is the largest value
DThe tallest column shows the range of the data
The tallest column shows the mode — the value that appears most often. The number 5 appears four times (more than any other), so it will have four X marks stacked above it, making it the tallest column. Option D confuses mode with range; the range is the spread from smallest to largest value (4 to 6), not a column height.
Question 2 Multiple Choice
What makes a line plot especially well-suited for measurement data, compared to a bar graph?
ALine plots use X marks instead of bars, which are easier and faster to draw
BLine plots can only show one category at a time, keeping the display simple
CThe positions on a line plot sit on a real number line, so the spacing between values is meaningful
DLine plots automatically sort data from smallest to largest for you
On a line plot, every position corresponds to an actual measured value on the number line, so the gap between 5 and 6 inches is the same size as the gap between 6 and 7 inches. This makes it easy to see clustering, gaps, and spread at a glance. A bar graph can display categories in any order; the spacing between bars carries no mathematical meaning.
Question 3 True / False
In a line plot, the tallest column of X marks identifies the mode — the measurement value that appears most often.
TTrue
FFalse
Answer: True
Each X represents one measurement. Stacking X marks above each value means the column height equals how many times that value appears. The tallest column is the one with the most X marks, which is exactly the mode — the most frequent value.
Question 4 True / False
To find the range of a line plot, you count the total number of X marks on the plot.
TTrue
FFalse
Answer: False
The total number of X marks tells you how many measurements were taken — that is the count, not the range. The range is found by identifying the smallest value and the largest value on the number line, then finding the difference between them. For example, if pencils ranged from 4 to 8 inches, the range is 4 inches.
Question 5 Short Answer
A student makes a line plot of pencil lengths and notices the X marks form two separate clusters — one near 4 inches and one near 7 inches — with no X marks in between. What does this gap tell you, and why is it easier to spot on a line plot than in a list of numbers?
Think about your answer, then reveal below.
Model answer: The gap means no pencils measured between 4 and 7 inches — the data falls into two separate groups. On a line plot, this gap appears as empty space on the number line between the two clusters, making it immediately visible. In a list of numbers, you would have to read every value carefully and compare them to notice that certain measurements are missing.
This is the key advantage of any data display: patterns that require effort to find in raw numbers become visible at a glance once the data is organized spatially. Gaps, clusters, and unusual outlier values all jump out visually in a way they cannot when data is just a sequence of digits.