Statistics 101L – Laboratory 2
For today's lab, you will collect more data, this time on variables that may be related. We will also
look more closely at the distribution of data using the statistical package JMP.
Activity 1:
Statistics is about variation. Your group will be doing basic research in morphology, the study of
form and structure in plants and animals. You are going to measure your height and your left and
right hand spans, the distance between the tip of your little finger and the tip of your thumb. To
measure your height you must remove your shoes. Stand with your back straight against the wall
and look straight ahead. Have a member of your group place a yard/meter stick flat on your head.
Make a small pencil mark on the wall (be sure to erase these afterwards). Measure the height in
centimeters. To measure your right hand span, put your hand on a ruler. Stretch your hand and
measure the distance, again in centimeters, between the tip of your thumb and the tip of your little
finger. Repeat this procedure with your left hand. Record your name, gender, height and hand
spans on your answer sheet.
Activity 2:
In this activity, we will look at the distribution of colors of plain M&Ms in Fun Size bags. This
will be done using the statistical analysis package JMP. Go to the course web page
(www.public.iastate.edu/~wrstephe/stat101L.html) and save the file M&M_Colors_S13 to the
desktop. Start JMP and open up the M&M_Colors_S13 data set. Use Graph – Chart to create a Pie
Chart for the distribution of colors. You have to include the Color Count as a Statistic for the % of
Total in order to get the right proportions. You can right click on the colors in the Legend and
change the colors to get a more appropriate display. Use Edit – Journal to place this output in a
journal. Change the Pie Chart to a Vertical Chart (bar chart). Use Edit – Journal to add this output
to your journal. Use the output to answer the questions on the lab answer sheet.
There were seven groups that collected data on M&Ms last week. Each group member collected
data on two bags of M&Ms. Use JMP to investigate if there are differences in the percentages of
different colors for the different groups. Use Fit Y by X where Color is the Y, Response and Group
is the X, Factor. Don’t forget to include Count as the Freq. Adjust the vertical axis so that the
increments are 0.10 instead of 0.25. You can right click on the display and Set Colors so that the
display colors are more appropriate. For the Contingency Table include just the Count and the
Row %. Use the output to answer the questions on the lab answer sheet. Use Edit – Journal to add
this output to your journal.
Save your journal to the desktop. Email your group’s journal to wrstephe@iastate.edu.
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Data Collection Sheet
Name
Gender Height (cm)
Right Hand Span (cm)
Left Hand Span (cm)
Questions for Activity 2:
a) Looking only at the Pie chart;
• Which color has the highest percentage? What is that percentage?
•
Which color has the lowest percentage? What is that percentage?
b) Looking only at the Bar chart;
• Which color has the highest percentage? What is that percentage?
•
Which color has the lowest percentage? What is that percentage?
c) Which display, Pie chart of Bar chart gives a more informative graphical display of the
distribution of colors in Fun Size Bags of M&Ms? Explain briefly.
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d) Look at the display of colors for the seven groups. For each color report the lowest and
highest percentage of that color and the associated groups. Compute the Range, the
difference between the Largest % and the Smallest % for each color. Note: Blue is done for
you.
Color
Smallest % (Group)
Largest % (Group)
Range
Overall %
Blue
17.16 (Group 4)
30.00 (Group 2)
12.84
22.72
Brown
13.15
Green
19.38
Orange
19.84
Red
12.80
Yellow
12.11
e) Some groups had only 3 students others had 4. Which groups had 3 students and which
groups had 4? How do you know?
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