Plots, Median and Mode
Lessons in this chapter
About Plots, Median and Mode
Data Handling in 4th grade introduces the idea of summarizing a data set with a single number, which is where statistics properly begins.
Create and Interpret Line Plots with Fractional Values continues 3rd grade's work, now with measurements in halves, quarters and eighths. Real measurements rarely land on whole numbers, so this is the realistic case rather than a complication.
Create and Interpret Stem and Leaf Plots introduces a format that keeps every original value visible while still showing the shape of the data. The stem is the tens digit and the leaves are the ones, so 23, 27 and 29 share a stem of 2 with leaves 3, 7 and 9.
Find Mode in Data Sets and Determine Median and Range of Data Sets are the conceptual step. The mode is the most common value, the median is the middle one when they are in order, and the range is the spread. Each answers a different question, and the median only works if the data is sorted first, which is the step kids forget.
All four lessons open as a 4th grade math worksheet in the page. Create and Interpret Line Plots with Fractional Values, Create and Interpret Stem and Leaf Plots and Determine Median and Range of Data Sets each set their own questions, scored as you answer them. They are free to try, with no login needed for your first 3.
Frequently asked questions
Create and Interpret Line Plots with Fractional Values continues the 3rd grade work with measurements in halves, quarters and eighths, and Create and Interpret Stem and Leaf Plots introduces a format that keeps every original value visible. Find Mode in Data Sets and Determine Median and Range of Data Sets are the conceptual step, since each answers a different question about the same data. The line plot work sits in Measurement and Data (4.MD); stem and leaf plots and the mode, median and range go beyond what the Common Core asks at this grade, which introduces measures of center in its 6th grade Statistics and Probability domain (6.SP).
The value that appears most often in a data set. A set can have more than one mode, or none at all if every value appears once.
The middle value once the data is sorted. Sorting first is essential and is the step kids most often skip. With an even number of values, take the mean of the middle two.
The difference between the largest and smallest values. It measures how spread out the data is, not what is typical about it.
A way of showing data that keeps every original value. The stem is the leading digit and the leaves are the last digits, so 23, 27 and 29 appear as stem 2 with leaves 3, 7 and 9.
Because real measurements rarely land on whole numbers. Heights and lengths come out in halves and quarters, so the plot has to handle them.