Getting Started 
Misconception/Error The student makes significant errors in scaling the horizontal axis. 
Examples of Student Work at this Level The student:
 Scales the axis disproportionately so that intervals of unequal length appear equal.
 Provides different degrees of scaling on different parts of the axis.
 Scales the axis in small increments so that the axis must be continued on a separate line on the paper.

Questions Eliciting Thinking What does a number line look like?
How did you decide how to scale the axis?
Could you have scaled your axis differently so that it does not need to be so long? 
Instructional Implications Review the concept of a dot plot and explain the important features of a dot plot:
 All possible values of the data are represented on an appropriately scaled horizontal axis,
 The number of dots above a value indicates the frequency of that value in the data set,
 Dots are placed in an evenly spaced vertical formation directly above their corresponding values,
 The horizontal axis is labeled, and
 The graph is titled.
Guide the student to construct a frequency table of the data in this task. Assist the student in identifying an appropriate range and scale for the horizontal axis. Ask the student to draw the axis and graph the data. Then ask the student to label the axis and title the graph. Provide feedback as needed.
Emphasize that the horizontal axis of a dot plot is just a portion of a number line that captures the range of data from least to greatest. The horizontal axis should be scaled so that the locations of the data points can be readily identified. On the other hand, the scale should allow for the data to be displayed on one line. Guide the student to observe that the data in the Chores Data task are multiples of five, extending from a low of 15 to a high of 60. So, a number line from 15 to 60 scaled by five is appropriate. Discuss with the student the importance of keeping a consistent scale on the number line.
Show the student a variety of examples of dot plots including some generated by technology. Describe features of the scale that make it appropriate to the data.
Provide additional opportunities to create dot plots for sets of data. 
Moving Forward 
Misconception/Error The student does not accurately or appropriately represent the data. 
Examples of Student Work at this Level The student scales the axis appropriately but:
 Uses differentsized symbols and/or places the symbols in a nonlinear arrangement.
 Attempts to use a variety of different symbols in the graph instead of just one.
 Uses an incorrect number of symbols for one or more categories.

Questions Eliciting Thinking What does each symbol in your graph represent? How many should there be for each measurement?
Why did you use different symbols? Can you think of why that may be confusing to the reader? Does each symbol represent the same amount or different amounts?
On this graph how can you tell which category has the highest count? The lowest count? What if your symbols were all the same size? Would that make it easier to read your graph?
I think you made a mistake with one of your frequencies. Can you try to find the error and correct it? 
Instructional Implications Guide the student to construct a frequency table of data before constructing a dot plot. Doing so will minimize data representation errors.
Provide the student with completed dot plots, and ask the student to determine the counts for each category of data. Point out that only one type of symbol is used and that equallysized and spaced symbols are placed in vertical columns to show the count for each data category. Explain to the student how this placement of the symbols helps one to quickly see which category has more and which has less as well as the overall shape of the distribution. Then ask the student to determine which data category has the least and greatest counts or frequencies. 
Almost There 
Misconception/Error The student makes a minor error in some component of the graph. 
Examples of Student Work at this Level The student scales the axis correctly and draws the correct number of symbols but makes any of the following errors:
 Does not include a title that describes the dot plot.
 Only includes numbers on the scale for which there are data.
 Extends the horizontal axis well beyond the range of the data.
 Inaccurately describes what each symbol represents in an included key.

Questions Eliciting Thinking If you showed your dot plot to someone from another class, would they be able to figure out what it represents? What is missing from your graph?
Can you think of a good title for your dot plot? Does your title let someone know what your dot plot is about?
Which numbers are missing from the scale on your axis?
What part of your axis was not used? Does it really need to be included in your graph? 
Instructional Implications Provide the student with additional opportunities to create line plots. Provide the student with a checklist of features that each line plot must include (e.g., a title, a labeled and scaled horizontal axis, and the correct numbers of dots placed in evenly spaced vertical formations).
Model for the student how to label a line plot with an appropriate title, axis label, and key.
Guide the student to select an appropriate lower and upper limit for the scale on the horizontal axis. Generally, this can be the largest whole number less than the smallest data value and the smallest whole number larger than the largest data value. 
Got It 
Misconception/Error The student provides complete and correct responses to all components of the task. 
Examples of Student Work at this Level The student correctly scales the axis using reasonable lower and upper limits, provides the correct number of symbols for each data category, places samesized symbols in linear arrangements, and includes an axis label and title.

Questions Eliciting Thinking Can you explain how and why you scaled your number line?
Can you find the mean or median from the dot plot? Which is easier to do? Why? 
Instructional Implications Give the student a completed dot plot and ask him or her to reconstruct the data in the form of a frequency table from the dot plot. Then ask the student to calculate a variety of statistics such as the mean and the mean absolute deviation or the median and the interquartile range. 