Saturday, May 9, 2015

7th Grade Ducklings Re-Engagement Task

Following the guidelines of SVMI after having 7th graders working on Ducklings MARS task: (credit to

This gives students a chance to find a median from a data table, calculate the mean, and interpret all of this in context when a duck family is added later on that does not change the mean.

Analyze errors in filling in question 1's frequency chart:

1. Filled out 7, 8, 9, 10, 11, 12
2. Filled out 7.5, 9, 10.5, 12, 13.5, 15

How does filling out the chart help you find the mean number of ducklings in a family?

Focus questions for Question 2 (finding the median):

  1. How do we ensure we have the correct amount of data? How can you verify it in more than 1 way? 
  2. Is there an even or odd amount of data?

Many students said median was 5.5 because 5+6/2 = 5.5.

Also, a few students said the median was 2, because 2 is the median of 1,2,2,2,2,4,6.

I know the median is ____ because there are _____ total ducklings which is an (even/odd) number. Since it's ______, there (is/isn't) a true median.

For question 3, show student methods for finding average without making mistakes.

Sentence Frame for question 4:

If there are _____ total ducklings and _____ families, one more family of ____ ducklings totals ______ ducklings in ____ families which has an average of _____ ducklings because _____/_______ = _____.

For students completely successful, how could you use a stem and leaf plot in this problem? Also a good follow up task is from the 2000 MARS tasks called "Supermarket" comparing estimations of median and mean.

Notes to self:

  • Highlight Chase's method of finding median and mean at the same time in an organized fashion.
  • Mention Rion's explanation for number 4 and also Joey's understanding of how mean works.

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