Grade 6 · Mathematics · 30 minutes
Unit 3 · Questions and data distributions · Lesson 1 of 1
Dot Plots and Reading-Time Distributions
Describe a small data set with a dot plot, center and variation.
Mr. S Teaches · Original starter mini-lesson · MS6-MATH-06Learning objective
Draw a dot plot, calculate a mean and explain how an unusual value changes the summary.
Before you begin
- Add and divide whole numbers
- Read a number line
Gather your materials
- Paper and pencil
- Ruler and graph paper
Language to know
- statistical question
- A question answered with data expected to vary.
- distribution
- How values are arranged across a data set.
- mean
- The sum of values divided by their count.
- mean absolute deviation
- The average distance of values from their mean.
Understand the concept
A statistical question expects different answers, such as how many minutes several learners read. A dot plot places one dot per observation, stacking repeats. The mean balances the data numerically, while mean absolute deviation describes their average distance from that balance point. A summary needs units and context, not just a computed number.
Teach it step by step
- Contrast “How long did Noor read?” with “How long did five learners read?” and discuss expected variation.
- Plot the fictional times 10, 10, 15, 20 and 20 minutes, using one dot per learner.
- Compute 75 ÷ 5 and mark the mean. Count distances from 15 to compute a mean absolute deviation.
- Replace one 20 with 50 and predict the direction the mean moves before calculating.
- Write two sentences describing center and spread without judging the learners.
Make the thinking visible
Worked example or model response
The mean is 15 minutes. Distances from 15 are 5, 5, 0, 5 and 5; the mean absolute deviation is 20 ÷ 5 = 4 minutes. Replacing 20 with 50 increases the total to 105 and the mean to 21 minutes.
Guided practice
For 2, 4, 4, 4 and 6 pages, draw a dot plot, find the mean and calculate the average distance from the mean.
Independent practice
1. Plot 5, 5, 10 and 20 minutes. Find the mean and median. 2. Describe why one summary number alone can hide a long reading time.
Quick assessment
What does each dot represent, and why must repeated values be shown separately?
Answer key & assessment criteria
Answers and teaching guidance
- Guided: Mean 4 pages; distances 2, 0, 0, 0, 2 give mean absolute deviation 0.8 page.
- Independent 1: Mean 10 minutes; median 7.5 minutes. 2: The single 20-minute value differs from the cluster near 5–10 minutes and raises the mean.
- Quick check: Each dot is one observation; repeats are separate learners or measurements, not extra copies of an error.
Look for: Look for an explanation of the choices, not only a final answer. Require units and a check against the context.
Make it work for your learner
More support
Use counters placed on a large number line and start with four whole-number values.
Extension challenge
Find a different five-value data set with mean 15 and a greater mean absolute deviation.
Selected contributions · Official sources
Standards connections
Contributes to Common Core standard
6.SP.B.4Common Core · Grade 6
Display numerical observations with a dot plot.
Read the official standard ↗This lesson contributes selected skills; it does not fully address the standard.
Source and mapping checked 2026-11-04. This mini-lesson contributes selected skills; it does not claim full attainment.
Contributes to Common Core standard
6.SP.B.5.cCommon Core · Grade 6
Describe center and variation and explain an unusual value in context.
Read the official standard ↗This lesson contributes selected skills; it does not fully address the standard.
Source and mapping checked 2026-11-04. This mini-lesson contributes selected skills; it does not claim full attainment.