# Day 93: Jelly Blubber Kinda Day

Today we completed the Jelly Blubber Activity…wish I knew who originally put this activity together, but it is a “classic” among high school statistics classes.  I first got the activity while attending an AP Summer Institute with Robin Rubinstein.  Over the years I’ve seen variations on the basic idea.  I adjust the content to fit the school and surrounding area.  The kids measure the lengths and record on their worksheet via their iPads.

Once they had their data, I used the Navigator to collect all of their sample averages and then displayed them so we could look at the approximate sampling distribution….great time to review the important concepts of a sampling distribution that we’ll use in inference.  Pretty nice displays, huh?  Actually we had a couple of “outliers” and the kids suggested that perhaps some students had entered their data in centimeters instead of millimeters.  Of course I praised them enthusiastically, pointing out how much they had grown in their ability to look at data critically.  When asked, a couple of them fessed up and so I adjusted those values and got the display below.  The predictability of the CLT never fails to amaze me!  Such a stats geek!

My students answered some more questions and were led through the process of calculating confidence intervals with a known population standard deviation, since there are only 100 total Jelly Blubbers.  I asked them to randomly select one of their five CI using randint(…I was worried that the time it’d take to have all of my students put up all 5 of their CI would take the whole period.  Using sticky dots, big graph paper, and markers, they drew in their chosen CI.  Didn’t finish so the rest is for tomorrow.