Histograms, Bar Graphs, Line Plots. Box Plots What do graphs tells us?

Standard MCC6.SP.5.b. Describing the nature of the attribute under investigation, including how it was measured and its units of measurement

How do the attributes of a graph inform me?

How do you know what is being described in a graph? 0 2 4 6 8 10 12 14 16 18 20 22 Number of Books How many books did 6th graders at Taylor Middle School read this summer? How do you know what is being described in a graph?

Reading a Histogram A histogram looks like a bar graph, except that answers are grouped together. On the x-axis at the bottom you will see the intervals. In this graph about the number of coins being brought for a coin drive, there were 3 students who brought between 0 and 4 coins. They might have brought 0 coins, or maybe they all brought 4, but we can’t tell. 8 students brought between 5 coins and 9 coins, Again, we can’t tell exactly how many each person brought, just how many brought between 5 and 9 coins.

Riley Middle School Coin Drive Number of Coins Brought by Students Riley Middle School Coin Drive 0-4 5-9 10-14 15-19 20-24 Let’s review how to read a histogram. A histogram looks like a bar graph, except that answers are grouped together. On the x-axis at the bottom you will see the intervals. In this graph about the number of coins being brought for a coin drive, there were 3 students who brought between 0 and 4 coins. They might have brought 0 coins, or maybe they all brought 4, but we can’t tell. 8 students brought between 5 coins and 9 coins, Again, we can’t tell exactly how many each person brought, just how many brought between 5 and 9 coins.

When students make graphs they sometimes forget to use titles, labels, and units. Let’s look at what these are and why they are important pieces of a graph.

Books Read This Summer by 6th graders at Taylor Middle School 0 2 4 6 8 10 12 14 16 18 20 22 Number of Books Books Read This Summer by 6th graders at Taylor Middle School Here is the line plot from the beginning of the lesson. The graph includes a title, and in this case the question that was asked is the title, and it says, “How many books did 6th graders at Taylor Middle School read this summer?” The next important piece of this graph is the label, which says, “Number of Books.” The label gives important information about the graph, because even with the title, we don’t know what each dot represents without it. Each dot is a response from a student, and we know from the label that they responded in the number of books they read, not chapters, genres, or pages, and we see that in the unit included in the label.

Riley Middle School Coin Drive Number of Coins Brought by Students Riley Middle School Coin Drive 0-4 5-9 10-14 15-19 20-24 Now let’s look at the histogram about the coin drive at Riley Middle School. Histograms should also include a title, which should give useful information about the topic of the survey. This title told us about the school and the coin drive, but we don’t know whether the teachers were included also and if the coins were measured by their value or number. Next the histogram includes labels on both the x axis, where it says, “Number of Coins Brought by Students.” This label provides this necessary information. The label on the y axis says, “Responses” and explains what the numbers are. Next we can look for the unit which is usually provided in the label. In this case it is coins. A histogram also includes the interval, which is the gap between each bar that includes any responses that fall within that gap.

Teacher Experience (in Years) Teacher Experience at Riley Middle School Now let’s compare these to a box plot. Like all graphs, box plots need to include a title to give us an idea of what the graph is about. It must also include a label so we know what each of the numbers mean, and in this case it is teacher experience. Finally there is a unit, which is years. This is equally important because we don’t know if the experience is measured in days, months, or years without it.

6th Grade Students’ Pets 0-1 2-3 4-5 6-7 8-9 10-11 Number of Pets 6th Grade Students’ Pets Now try a problem on your own. Identify the attributes of this histogram. Hit pause while you work on the problem, and then push play again to hear my answers. This histogram contains a title of 6th grade students’ pets. It also includes labels that say number of pets and responses. It’s a histogram so the intervals are marked as every 2. We can tell from the graph that 12 6th graders identified that they have 0 or 1 pet. 6 students have 2 or 3 pets, and 2 students have 4 or 5 pets. There is a gap from 6 through 9 because no one responded in those intervals. Finally, 1 student responded that he or she 10 or 11 pets.

Number of Mistakes 6th Graders’ Mistakes on Spelling Tests