© 1999 T
EXAS
I
NSTRUMENTS
I
NCORPORATED
TI
-
34
Û
: A Guide for Teachers
18
Heart Rates—1-Variable Statistics
(Continued)
For an example, we assume a class of 22
students, three having a heart rate of 60, five
with a rate of 61, six with 62, three with 63,
one with 64, and four with 65.
4.
Check the statistics calculations. After
students display
Ò
x
(Sigma x), explain that
Ò
x
is the sum of all the heart rates. Ask:
How many heartbeats were there in one
minute? Is the average heart rate higher or
lower than you expected?
The numbers show the results of the example
described above. The results your students
obtain will vary depending on the size of the
class or group, and the heart rate readings.
5. Now we will see the effect of some exercise
on heart rate. Tell the students:
If at any point during this portion of the
activity you experience pain, weakness, or
shortness of breath, stop immediately.
6.
Have the students run in place for 2 minutes
and then give them these instructions:
a
.
Time your pulse for 1 minute.
b.
Record your heart rate as before.
c.
Enter the data into the calculator.
d.
Compare the average heart rate after
running with the resting heart rate.
5. Repeat steps 3 and 4.
1
Press
u
.
n
should equal
the total number of students
sampled.
n
Ï
Sx
Î
x
¹
22
2. Press
"
to
Ï
to see the
average heart rate.
n
Ï
Sx
Î
x
¹
62.27272727
3. Press
"
"
"
to
Ò
x
.
Ò
x
Ò
x
2
¹
1370
7.
Now have the students do jumping jacks for 2
minutes. Instruct them to time their pulse for 1
minute again and record as before. Have them
enter the data into the calculator again and
calculate the average heart rate after jumping
jacks. Compare to the other two averages.
8
How fit is the class? If the class (or individual)
heart rate after jumping jacks is less than 90,
then you are in great shape. If it is higher than
125, then you are in poor shape.
9.
Instruct students to make a histogram of the 3
sets of data they collected. Ask students:
How are the histograms the same? How are
they different? Is the data grouped the same
or is it more spread out in one graph
compared to another?
