Pre-Algebra
Data and graphs
Dot plots and histograms
20 practice questions
0 video lessons
Theory + worked examples
Dot Plots and Histograms
Texas Pre-Algebra (TEKS) • Standard 6.12(A) • Data & Graphs
Dot Plots and Histograms is a topic in Data & Graphs in the Texas Essential Knowledge and Skills. It is aligned to Standard 6.12(A), which requires students to construct and interpret dot plots and histograms.
Dot plots show each data value; histograms group values into intervals with bars.
Theory
A dot plot stacks one dot per data value; a histogram uses bars for the frequency in each interval.
Both show the shape of the distribution — center, spread, and gaps.
A dot plot and a histogram.
Comparing the two.
Frequency:
\[\text{bar height}=\text{count in that interval}\]
Histograms have no gaps between bars.
How to read these displays
- Dot plot: count dots above each value.
- Histogram: read the bar height for each interval.
- Look for the center and spread.
- Note peaks and gaps.
Example 1 — Read a dot plot
If \(4\) has \(4\) dots, how many data points equal \(4\)?
Solution
Count the dots.
| \(4\) |
Example 2 — Histogram bar
What does the height of a histogram bar show?
Solution
The frequency (count) for that interval.
Example 3 — Which for intervals
Which display groups data into ranges?
Solution
A histogram.
Example 4 — Shape
What do both displays reveal?
Solution
The shape of the distribution.
Common pitfalls
Histogram bars touch; bar graphs have gaps.
Each dot is one data point.
Histograms group, dot plots don't.
Frequently asked questions
What is a dot plot?
A display with one dot per data value.
What is a histogram?
A display of frequencies over intervals.
What does bar height show?
The count in that interval.
Do histogram bars touch?
Yes.
More in Data and graphs