Dot Plot Maker & Generator
A dot plot maker for statistics homework, AP Statistics and lab reports: one dot per value stacked over a number line, two groups on aligned lines, and the mean, median, quartiles and shape worked out from your numbers before anything is drawn.
Journal styles in the dot plot maker
Five presets of the dot plot maker, each on its own study: dendritic spine density in two mouse lines, great tit clutch sizes, CD8+ T cells under three treatments, hospital stay in two trial arms and hours of sleep before an exam. Click a card to apply the style or load its values.
Dot plot examples
Four dot plot examples from the dot plot maker, each drawn from the prompt and values on its card: a quiz with its shape described, a count that is skewed right, two classes on one number line and a quarter-inch measurement with fraction labels. Click any card and its prompt and values drop into the composer.
What is a dot plot?
A dot plot (called a line plot in elementary school) shows a set of numbers as dots over a number line: each observation is one dot, and repeats of the same value stack into a column, so the height of a stack is how often that value occurs. Every data point stays visible, which makes the shape, centre and spread of a small data set readable at a glance. That is why Grade 6 (Common Core 6.SP.4) and AP Statistics use it as the first display of a distribution.
About this dot plot creator
- Type values straight into the dot plot maker (Scores: 6, 7, 7, 8, 8…), one group per line, or attach a spreadsheet (.csv, .tsv or .xlsx, three at most) laid out one column per group.
- The dot plot maker counts every stack in code before drawing: the stack height over each value, the number line and its ticks, and a count check that the stacks add up to n.
- Ask the dot plot maker for the mean, median, mode, range, quartiles, a percentile or a written description of the shape, and it prints numbers computed from your values, never estimated by the image model.
- Give the dot plot maker two or more groups and it draws a double dot plot: one row each on identical number lines, so equal values line up and centres and spreads can be compared by eye.
- In the dot plot maker whole numbers get one stack per value, quarter and eighth inches get fraction labels, and values too fine to stack are rounded to a clean step for stacking only; the statistics keep the exact values.
How to make a dot plot with the dot plot maker
- 1
Give the dot plot maker your values
Type them into the dot plot generator after a label, Pets: 0, 0, 1, 1, 1, 2…, writing a repeated value as often as it occurs. A second line is a second group on its own row. A spreadsheet works too: one column per group, or long form with group names in one column and values in the next.
- 2
Say what the dot plot should show
Tell the dot plot maker the axis title, then anything to mark: the mean, median, mode, range, Q1 and Q3, the 90th percentile, a frequency axis, mean ± SD for lab data, or “describe the shape”. Say vertical for columns with values on the y axis.
- 3
Generate it and count one stack
The dot plot maker draws from the computed stacks, so the tallest column holds exactly as many dots as your data say. Check one stack against your tally, ask for changes in the chat, then export PNG, SVG or PPTX.
Parts of a dot plot
Six parts a teacher checks on a hand-drawn dot plot, and the ones the dot plot maker fixes in code before the figure is drawn.
- Number line
- A horizontal scale that covers the data with one equal step between ticks; it starts one step below the smallest value (or at 0 for counts) and ends one step above the largest.
- Dots
- One per observation, all the same size and the same distance apart, so a stack of six is visibly one mark taller than a stack of five.
- Stacks
- Repeats of a value pile straight up over its tick, never between two ticks. The tallest stack is the mode, and the dot plot maker counts every stack before drawing it.
- Title and axis label
- Say what was counted and the unit, Number of pets or Height (cm). There is no y axis on a plain dot plot; a frequency dot plot adds one.
The dot plot maker as a mean, median and mode calculator
Fifteen students reported how many books they read over the summer. The dot plot maker turns the list into stacks; the same stacks give every number a dot plot question asks for, read off the frequency table below.
| Books (x) | Frequency (f) | x × f | Running count |
|---|---|---|---|
| 0 | 1 | 0 | 1 |
| 1 | 2 | 2 | 3 |
| 2 | 3 | 6 | 6 |
| 3 | 4 | 12 | 10 |
| 4 | 2 | 8 | 12 |
| 5 | 1 | 5 | 13 |
| 6 | 1 | 6 | 14 |
| 11 | 1 | 11 | 15 |
| Total | 15 | 50 |
- 1
Mean: total every value
Multiply each value by its stack height and add: 50 books ÷ 15 students = 3.33. On the dot plot this is the balance point, which the dot plot maker marks with a small triangle under the line.
- 2
Median: count to the middle value
With 15 values the median is the 8th from the left. The running count passes 6 at 2 and reaches 10 at 3, so the 8th one is in the stack at 3: median = 3.
- 3
Mode and range: tallest stack, end to end
The tallest stack, 4 high, is at 3, so the mode is 3. The range is the largest value minus the smallest: 11 − 0 = 11.
- 4
Quartiles and the outlier
Leave the median out and split the rest: the lower 7 values (0, 1, 1, 2, 2, 2, 3) have median Q1 = 2, the upper 7 (3, 3, 4, 4, 5, 6, 11) have Q3 = 4, so IQR = 2. The upper fence is 4 + 1.5 × 2 = 7, which makes 11 an outlier.
- 5
Percentiles: count values at or below
For the 80th percentile take the value at rank ⌈0.8 × 15⌉ = 12: the running count reaches 12 at 4, so it is 4 books. A student who read 5 books is at or above 13 of the 15 values, the 87th percentile. Ask the dot plot maker for “the 80th percentile” and it draws the line there.
The mean (3.33) sits to the right of the median (3) because one reader at 11 pulls it; without that dot the mean is 39 ÷ 14 = 2.79. When a dot plot has an outlier or a long tail, quote the median and IQR. Send the list to the dot plot maker to draw every mark on this figure from the same counts.
How to describe the distribution of a dot plot
A full answer names four things, in context and with numbers: the shape, any outliers, the centre and the spread (SOCS in AP Statistics). Read the shape first, because it decides which centre and spread to quote: mean and standard deviation for a roughly symmetric dot plot, median and IQR for a skewed one or one with outliers. The dot plot maker names the shape from the stacks it counted, with outliers set aside first.
Roughly symmetric
The stacks fall away about equally on both sides of the middle; mean and median are close.
QuoteMean and SD (or median and IQR)
Skewed right
Most values sit at the low end with a long tail of a few large values to the right; the mean is pulled above the median.
QuoteMedian and IQR
Skewed left
The values pile up at the high end and trail off to the left, as on an easy test; the mean sits below the median.
QuoteMedian and IQR
Roughly uniform
Every stack is about the same height across the range, as with 60 rolls of a fair die; there is no peak.
QuoteMedian and range
Two peaks (bimodal)
Two separate tall stacks with a dip between them usually means two groups were mixed, such as two classes or two species.
QuoteDescribe each peak
A cluster and a gap
Most values bunch together and an empty stretch of the number line separates a few others; name the cluster's limits and the gap.
QuoteMedian and IQR
An outlier
A value far from the rest, beyond Q3 + 1.5 × IQR or below Q1 − 1.5 × IQR, is an outlier; check it is not a typo before describing the rest.
QuoteMedian and IQR, outlier named
A model answer for the books data
The distribution of books read is roughly symmetric from 0 to 6 with an outlier at 11 books. The median is 3 books and the IQR is 2 books; the mean (3.33) is pulled above the median by the outlier. There is a gap from 7 to 10 books.
Ask the dot plot maker to “describe the shape, centre and spread” and it prints the same four parts under the figure, from the same counts that place the dots. Each card above loads a dataset of that shape.
What the dot plot maker can draw
Seven kinds of dot plot that come up in worksheets, AP Statistics and lab reports, what sets each apart and how to ask the dot plot maker for it.
Dot plot with fractions (line plot with fractions)
Measurements to the nearest ½, ¼ or ⅛ of a unit, plotted on a number line labelled in fractions, as in Common Core 4.MD.4 and 5.MD.2. Type the values as decimals (1.25 for 1 ¼) and say “fraction labels”: the dot plot maker labels the ticks 1, 1 ¼, 1 ½ … and stacks each measurement over its own fraction.
Double dot plot
Two groups on two identical number lines, one above the other, so equal values line up. It is how Grade 7 (7.SP.3) and AP free-response questions compare two distributions; ask the dot plot maker to compare the centres and spreads and it prints which group has the higher median and which is more spread out.
Frequency dot plot
A dot plot with a vertical frequency axis, so the height of each stack can be read off a scale instead of counted. Useful once stacks pass ten dots. Say “frequency axis” and the dot plot maker adds a y axis from 0 to the tallest stack.
Dot plot with mean and median
The mean shown as a small triangle under the number line (the balance point) and the median as a dashed line, both at their computed values. Seeing the two apart is the quickest way to show skew or the pull of an outlier; the dot plot maker places both from the values, not by eye.
Dot plot of a sampling distribution
Each dot is one simulated sample's statistic, such as a sample proportion, and the plot shows how the statistic varies from sample to sample. AP Statistics reads bias from where the points centre against the true value and variability from how widely they spread: a tight cluster away from the true value is high bias, low variability. Paste the simulated statistics into the dot plot maker with the true value as a marked line.
Dot plot with mean and error bars
The research form: one column per condition, values on the y axis, every replicate or animal its own dot, with the mean ± SD or ± SEM beside it. Small-n experiments are shown this way because a bar of the mean alone hides the points; say vertical and mean ± SD to the dot plot maker.
Dot plot of a large data set
When a stack would pass about 24 marks, each one stands for several observations and a key says so (each symbol = 5 students). The dot plot maker picks that unit itself; past a few hundred values a histogram usually reads better, and the histogram maker takes the same list.
Dot plot vs histogram vs scatter plot
A dot plot and a histogram both show one numeric variable; the dot plot keeps every value, the histogram groups values into bins. A scatter plot needs two variables per subject. A line plot in elementary maths is the same figure as a dot plot, drawn with X marks instead of dots.
| Dot plot | Histogram | Scatter plot | |
|---|---|---|---|
| Each mark is | One observation, one dot over its value | A bar per bin; its height or area is the count | One subject, placed by two measurements |
| Variables | One numeric variable, per group | One numeric variable | Two numeric variables |
| Individual values visible | Yes, every one | No, only which bin it fell in | Yes |
| Suits | Small to moderate data sets, up to roughly 100 values | Moderate to large data sets | Any size; relationships, not distributions |
| Mode reads as | The tallest stack | The tallest bar (modal class) | Not applicable |
| Comparing groups | Rows on aligned number lines | Overlaid, stacked or side-by-side panels | Marker shape or colour per group |
Same numbers, different question: draw each value in the dot plot maker, bin a long list in the histogram maker, summarise it to five numbers in the box plot maker, or pair it with a second variable as a scatter plot.
Dot plot questions and answers
Eleven bean plants grew in sun and eleven in shade for 14 days. These are the questions a dot plot worksheet asks about a figure like this one, drawn here the way the dot plot maker lays out two groups; open each answer after trying it.
1.Which dot plot represents the data set 4, 5, 6, 7, 7, 7, 8, 8, 9, 13?
Neither row. The Shade row has eleven dots: the list is missing one of its two 6s. Matching a list to a dot plot means checking every stack height, not just the range.
2.What is the median height in each row?
Sun 12 cm, Shade 7 cm. With 11 plants the median is the 6th from the left: in the Sun row that plant is in the stack at 12, in the Shade row in the stack at 7.
3.Find the mean height of the Shade plants.
7.27 cm. Add every plant's height: 4 + 5 + 6 + 6 + 7 + 7 + 7 + 8 + 8 + 9 + 13 = 80, then divide by 11. The mean is above the median of 7 because the plant at 13 pulls it right.
4.Which row has the greater spread?
It depends on the measure. The Shade row has the larger range (13 − 4 = 9 against 15 − 9 = 6), but both rows have an IQR of 2 cm (Shade 8 − 6, Sun 13 − 11). The range is driven by the single plant at 13.
5.Is the Shade plant at 13 cm an outlier?
Yes. Q1 = 6 and Q3 = 8, so IQR = 2 and the upper fence is 8 + 1.5 × 2 = 11. 13 is beyond the fence. Check for a mislabelled pot before dropping it.
6.Compare the two distributions.
Plants in sun grew taller: their median height (12 cm) is 5 cm above the shade plants' median (7 cm). Both rows are roughly symmetric with the same IQR of 2 cm; the shade row has an outlier at 13 cm. The rows overlap only from 9 to 13 cm.
7.A simulation's dot plot of 50 sample proportions centres at 0.62 and spreads only from 0.58 to 0.66, while the true proportion is 0.50. Describe its bias and variability.
High bias, low variability. The estimates cluster tightly, so the method gives consistent answers, but they centre far from 0.50, so it is consistently wrong. A larger sample would shrink the spread further but not fix the bias; a better sampling method would.
Have a worksheet of your own? Paste its numbers into the dot plot maker, one line per group, and check your answers against the medians and spreads it prints.
Dot plot maker vs Excel, Google Sheets, Desmos and R
Excel and Google Sheets have no dot plot chart type, Desmos and R do. Here is where each one, and the dot plot maker, leaves the counting, the statistics and the second group.
| This dot plot maker | Excel | Google Sheets | Desmos | R (ggplot2) | |
|---|---|---|---|---|---|
| Getting a dot plot | Type or attach the values; stacks counted in code | No chart type: add a COUNTIF running-count column and plot it as an XY scatter with markers only | Same workaround: running-count column, scatter chart, gridlines and y axis hidden | dotplot(list) in the graphing calculator, bin width set by hand | geom_dotplot(binwidth = 1); the y axis it draws is meaningless and must be hidden |
| Two groups | Rows on aligned number lines from two lines of values | A second series offset by hand | A second series offset by hand | A second dotplot() of the second list | facet_wrap() or a group aesthetic |
| Mean, median, mode | Computed and marked on request | Separate formulas in cells | Separate formulas in cells | mean() and median() typed separately | Separate calls; marks added as layers |
| Quartiles, outliers, shape | Median-of-halves Q1, Q3, 1.5 × IQR outliers and shape words printed | QUARTILE.EXC formulas, nothing on the chart | QUARTILE formulas, nothing on the chart | quartile() typed separately | fivenum(); shape described by you |
| Fraction labels | Quarters and eighths labelled as fractions | Fraction number format (# ?/?) on the axis | Fraction number format on the axis | Decimal ticks | A label function such as MASS::fractions |
| Finish | Classroom or journal style, PNG, SVG or PPTX | Office chart styling | Sheets chart styling | Screenshot or image export | Full control, in code |
Numbers already in a spreadsheet? Attach the .xlsx to the dot plot maker unchanged: one column per group with its name in the header row, or long form with group names in one column and values in the next.
Dot plot maker questions, answered
How do you make a dot plot?
Draw a number line that covers the smallest to the largest value in equal steps, then put one dot above the line for every observation, stacking repeats straight up. Give the plot a title and an axis label with the unit. The dot plot maker does all of this from a typed list: count one stack against your data to check it.
How do you find the mean on a dot plot?
Multiply each value by the number of dots above it, add the products and divide by the total number of dots. For stacks of 1, 2 and 3 over 4, 5 and 6 the mean is (4 + 10 + 18) ÷ 6 = 5.33. Ask the dot plot maker to mark the mean and it computes it the same way.
How do you find the median of a dot plot?
Count the dots from the left to the middle one: the ((n + 1) ÷ 2)th dot. With an even count, average the two middle values: with 20 values the median is halfway between the 10th and 11th. The dot plot maker draws the median as a dashed line when asked.
Is a line plot the same as a dot plot?
Yes, in school maths: a line plot shows each value as an X or a dot over a number line, which is a dot plot. Grades 2–5 call it a line plot; from Grade 6 on it is a dot plot. A line graph, which joins points over time, is a different chart.
How do you make a dot plot in Excel?
Excel has no dot plot chart, so add a running count beside the sorted values (=COUNTIF($A$2:A2, A2)) and chart the two columns as an XY scatter with markers only. Then hide the y axis and gridlines. The dot plot maker skips the workaround: attach the sheet as it is.
How do you make a dot plot with fractions?
Mark the number line in the fraction the measurements use, such as quarters (0, ¼, ½, ¾, 1, 1 ¼ …), and stack one dot per measurement over its fraction. In the dot plot maker type the measurements as decimals and say “fraction labels”: quarter and eighth values are labelled as fractions.
When should you use a dot plot instead of a histogram?
Use a dot plot when the data set is small enough to show every value, roughly up to 100, and a histogram when it is larger or the values are continuous and rarely repeat. A dot plot keeps exact values and gaps visible; a histogram hides them inside bins. The dot plot maker and the histogram maker both read the same pasted list.
How many values can the dot plot maker take?
The dot plot maker takes up to 800 values across as many as six groups, with no limit on the range. Past about 24 in one stack it lets each mark stand for several observations and prints a key; past a few hundred values, a histogram is usually clearer.
Is this dot plot generator free?
Yes, to begin with: signing up gives 100 free credits and asks for no card. Counting the stacks and working out the statistics in the dot plot maker cost nothing; credits are spent when the figure is drawn.
What is a Cleveland dot plot?
A Cleveland dot plot shows one value per category as a dot on a common scale, categories listed down the side and sorted by value, as a lighter alternative to a bar chart. It is a different figure from the distribution dot plot the dot plot maker draws, which shows every observation of one variable.
What is a dot-and-whisker plot?
A dot-and-whisker plot shows estimates, such as regression coefficients or effect sizes, as dots with whiskers for their confidence intervals. It summarises models rather than raw data. For study effects with a pooled estimate, use the forest plot maker.
Is this the Federal Reserve dot plot?
No: the Fed dot plot charts each FOMC member's projection of the policy rate. This page makes statistics dot plots of your own data.
Sources
- Dot Plots — Leland Wilkinson, The American Statistician 53(3): 276–281 (1999)
- Grade 6 Statistics & Probability, 6.SP.B.4 — Common Core State Standards Initiative
- geom_dotplot: Dot plot — ggplot2 reference, Posit
- Statistics in the graphing calculator — Desmos Help Center
Keep exploring
Our other diagram tools, and the guides behind them.
Tools
Put your numbers into the dot plot maker
Type or attach your values and the dot plot maker returns a finished dot plot, every stack counted and every statistic you ask for computed from the same numbers.
Open the dot plot maker