Practice Graphing Using GMRI Green Crab Data on Tuva

Students will practice using data to answer statistical questions using the online interactive, Tuva. Students will create graphs and then use their graphs to draw meaning from the data. Tuva hosts a variety of datasets with accompanying questions that students may explore on their own or with extra class time. Use this lesson if students need extra support with statistical thinking.

Learning Outcomes: Students will be able to…

  • Organize data in order to answer a statistical question
  • Use data in a graph to provide evidence to support claims
  • Describe variability in a data set.

Standards Alignment:

MLR / CCSS / NGSS
B1 – The Skills and Traits of Scientific Inquiry: Students plan, conduct, analyze data from, and communicate results of investigations, including simple experiments. / CCSS.MATH.CONTENT.6.SP.B.4: Display numerical data in plots on a number line, including dot plots, histograms, and box plots. / MS-LS 2-1: Analyze and interpret data to provide evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem.

Materials

Access to the internet

Student notebook and glossary pages (printed or shared electronically)

Teacher preparation:

1. Watch the Tuva tutorial to familiarize yourself with Tuva tools:

2. Preview the GMRI Green Crab data on Tuva:

3. Optional: Create a free Teacher account on Tuva: (data is available without a login). This will allow you to upload your own data to analyze in Tuva.

4. Review and adapt the student handouts for the lesson.

Lesson Steps:

1. Explain to students that they are going to build on their skills of analyzing data to answer a scientific question. In this activity, they will practice creating graphs and interpreting the data in them. They will use data collected by other students through Vital Signs.

2. Introduce the problem of Green Crabs. See the background information on the Vital Signs Green Crab missions: ,

3. Explain that students from James Doughty Middle School in Bangor been monitoring Green Crab populations, trying to understand how they are spreading and changing over time. They will contribute to this mission by working to understand the data.

4. Introduce students to Tuva:

  • Ask students what they think each blue dot represents. If needed, explain that each dot is a data point of a green crab observation.
  • Give time for students to explore how to drag attributes to the x and y axis, and how that process affects the organization of the data points
  • Show where the “reset” button is located
  • Have students click on different graph names to try the different types of graphs.

5. Model the analysis of the first graph with your class. Use the following talking points to guide you. Start with the question, “What size are green crabs?”

a. Show the picture of the green crab that comes up when you open the dataset (click the “refresh” button to bring the photo back up). Point out the carapace and explain that “carapace” is a measurement of the body of the crab. Close the photo to look at the data again, and drag the “Carapace” to the X axis.

b. Remind students that each blue dot represents an observation of a crab caught by a student team.

c. Explain that you are going to give the graph a title that will help communicate what is being shown. Click on “Dot Plot (click to edit)” and title the graph “Size of carapace of Green Crabs Caught by James Doughty Students 2006-2013.”

d. Point out that you have organized the data into a dot plot. Challenge students to explain what information is shown in the dot plot (students should mention that it shows all the different carapace sizes that were recorded). Click on different types of graphs that can be used to show this data. Note that the line graphs and bar graphs have confusing results because there is no relationship to explore or no groups to compare in the question.

e. Return to the dot plot. Describe what you notice about the shape of the graph. In this case, most of the data is clustered between 1 and 5 cm. Students might also notice that most observations fall around the cm or ½ cm marks (not in between). Invite students to share ideas of why that might be (observations were most likely rounded to the nearest ½ cm).

f. Point out the outliers of the 8 and 9 cm carapaces. If needed. Define “outlier” as a data point that is different from the others and does not fall into trends.

g. Lead students through finding the range in the data.

h. Introduce a new tool. Show the measures of center on the graph. Go to the tab “Stats” tab at the top of the graph. Click on “mean,” “median” and “mode.” Challenge students to think about why the mean is greater than the median and mode.

i. Ask students about variability in the data. What might be the cause of the variability? Why are some crabs larger than others? Why might some teams have gotten a carapace size of zero cm? Encourage students to think about human error and natural variability.

j. Have students share their thoughts on the answer to the question, “What size are green crabs?” Encourage students to support their ideas with all the information they just generated, including range of data, measures of center, and shape of the graph.

6. Have work in pairs through the directions and questions in their student handouts to answer the rest of the questions using the green crab data. Students are likely to struggle with interpreting this data. That is ok! Make sure they take note of any questions or sources of frustration.

7. Students that finish before others should explore other Tuva datasets and experiment with different ways of organizing data.

  • Many of the datasets have activities with questions and answers built in. You can choose to have student complete these activities.
  • Encourage students to try using different types of graphs to answer questions about the data. Have them compare what they see on Tuva to the graphs in the chart.
  • If time allows, consider giving all students the opportunity to play around and find different activities that are interesting to them. The more practice graphing and answering questions, the better prepared they will be to analyze their own data.

8. Have students share what they learned about green crabs from this data. What answers weren’t so clear? What frustrations did they have working with this data? What made it messy or confusing? If they were conducting this investigation, what else would they try to find out?

9. Once students have completed the work, invite students to share the different graphs that they constructed and meaning that they made from these graphs.

10. Ask students how they think this practice might help them with analyzing their data. What have they learned about working with data?

Name: Date:

Using Tuva to Analyze Data: Green Crabs

Essential Question: What tools can I use to understand my data?

Key Vocabulary: trend, outlier, range, mean, median, mode

Do Now: Why do we graph data? How does a graph help us understand our results?

After completing this this activity, I will be able to…

NGSS Practice 4 / Level 1 / Level 2:all of level 1 and… / Level 3:all of level 2 and… / Level 4:all of level 3 and…
Analyzing Data / Use online tools to create different types of graphs. / Use my graph to answer a statistical question. / Use statistical thinking, like thinking about and describing the range of data, mean, median, mode, and variability to support my answer. / Make a new graph with given data and generate a question and claim based on the graph I make.

Once you have completed the activity, circle the highest level that you achieved.

Question 1: What size are green crabs?

Note: “Carapace” is a measurement of the shell of the body of the crab.

Directions:

  1. Go to to access the green crab data set.
  2. If this is your first time using Tuva, watch the tutorial video, labeled with a “T,” in the bottom right corner of the screen.
  3. To see a distribution the green crab observations arranged according to the size of the carapace, drag “Carapace” to the x axis.
  4. Give your graph a title. Click where it says, “Dot Plot (click to edit)” and type, “Size of carapace of Green Crabs Caught by James Doughty Students 2006-2013.”
  5. Go to the “Stats” tab above the graph and click on “Mean,” “Median,” and “Mode” to show the measures of center for this data.

Analysis questions:

1. What information does this graph give you? What do the dots represent? How are they organized? Explain what this graph shows in two sentences or less.

2. What do you notice about the shape of this graph? Are there more data points to the left side or the right side? Is the data clumped together or spread out? Is there anything interesting about the shape?

2. What is the range in size of the carapace? Find the range by subtracting the lowest carapace measurement from the highest carapace measurement.

3. What outliers do you see? An outlier is a point that stands out because it is different from most of the rest of the data.

4. Were all the carapace measurements about the same, or is there a lot of difference (also known as variability) in the measurement? What might be the cause of the differences?

5. What do the mean, median, and mode tell you about this data?

6. What size are green crabs in Belfast, Maine?

7. How did you come to this answer?

Question 2: Did the size of green crabs change over time?

Directions: Now let’s look at the size of the carapace in each year sampled.

  1. Drag “Year” over to the y axis to divide the data by year.
  2. Edit your title so that it now reads, “Size of Green Crabs Caught by James Doughty Students by Year, 2006-2013.”

Analysis Questions:

1. Describe the shapes of the different graphs. In which years is the data spread out? In which years is it clumped together? Is the data clumped farther to the left in some years than others? Are there any years that stand out to you?

2. Find the range for each year.

3. Do you see any outliers? What years are they from?

4. Which years have the most variability? Which have the least?

5. Did the size of green crabs change over time?

6. What evidence supports your answer?

Question 3: Which are larger, male or female green crabs?

Directions:

  1. Change your graph so that instead of comparing years of green crab data, you are comparing the size of the different genders.
  2. Edit your title so that it matches the information in the graph.

Analysis Questions:

1. What do you notice about the shapes of the graphs?

2. How much variability do you see in males versus females?

3. Which are larger, male or female green crabs?

4. What evidence supports your answer?

5. How sure are you? What questions do you have? What do you want to know about the data to make a stronger conclusion?

Question 4: Your question!

Directions:

  1. Arrange the data in a new way to make a different graph. Give your graph a title.
  2. Write a question based on the graph that you have created.
  3. Make a claim using evidence from your graph

Sketch of your graph (include x and y axes and a title in your sketch):

Question:

Claim: What is the answer to your question?

Evidence: What do you see in your graph that helped you come to this answer?