http://betterlesson.com/lesson/442525/in-the-middle
Objective: SWBAT find the mean of a frequency distribution,
assuming a normal distribution.Big Idea:Too much data! Too many
numbers! Use a frequency distribution to find the
mean.Standards:HSS-ID.A.2HSS-ID.A.3HSS-ID.A.4HSS-ID.C.8HSS-IC.A.1HSS-IC.A.2HSS-IC.B.3HSS-IC.B.4HSS-IC.B.5HSS-IC.B.6MP2MP4MP5
Set the Stage10 minYouwill want to have a copy of a very large
data set ready to show your students for this section of the
lesson. Thisshould be the samedata they will be working with in the
Put it into Action section, but you may want to have additional
data sets as well, to emphasize large data sets. I beginclass with
the following question on the board, "Describe three measures of
center". As my students come into the room I listen to their
discussions and can quickly gauge how much time I'll need to spend
setting up today's lesson. After the bell, Iask for a volunteerto
write the measures on the board. I allow them to "use a lifeline"
if necessary, but generally this is review and my students do
fairly well with it.Since we'll be working with some new concepts
later, I like to begin with something reassuring for them.When the
words "mean, median, mode" are posted, I ask my students to pair
share what each word means, mathematically. I then call on random
teams toshare their discussionwith the class.When we're all clear
on these terms, I ask my studentswhich one is the best
representation of the center of a data set. This is a bit tougher
because there are circumstances for which each is better than the
others. I allow the discussion to go for a bit, asking leading
questions until my students recognize that if the data set is
unimodal without outliers or much skewness, the mean works
best.Again, this should be review, so it doesn't take very long and
is a good opportunity to set things up for the rest of the
lesson.Once we establish that we'll be working with the mean, I
write a short set of numbers on the board and ask them to find the
mean individually without their calculators (or cell phones!) I use
a simple set like (5,5,8,10) and ask for a volunteer to work the
problem on the board. There are usually several willing students
and we quickly finish our review by following as the volunteer adds
the four numbers to get 28then divides by n=4 to get the answer of
7. To finish this section of the lesson, I project the Height
Weight Data set on my whiteboard and challenge my students to again
find the mean, telling them they can work with either height or
weight. Amid the chorus of groans that ensue there is almost always
some student who asks to use the calculator.(MP5) I turn off the
projection and assure them that we will eventually be using both
calculators and computer software like Excel, but that for today's
lesson I'm going to show them another way to estimate the mean that
goes much more quickly.
Put it into Action40 min
See video on website.Wrap it Up5 minI allow students who need
additional time to write their responsesto the handout to turn in
their work at the beginning of class tomorrow and otherwise collect
the assignment at the end of class.When all teams havecompleted the
activityincludingtheir written responses to the questions on the
handout, I ask them to pair-share the following discussion
questions: What part of this activity was most difficult and why?
What part of this activity was easiest and why? Would you have
preferred to find the mean of this data (by hand) without using a
frequency table and why?I have my students do this closure piece
both so that they have a structured opportunity to reflect and so
that I can listen for persistent misconceptions or concerns as I
walk around.
