Statistics 101L – Laboratory 3
The activities in this lab look at the distribution of the measurements. You will use JMP
to display the distributions of different measurements, weights of Fun Size bags of
M&Ms and heights of students in the class. You will also look at explaining variability
in the heights of students by considering the gender of the students.
Activity 1:
In this activity, we will look at the distribution of the Total Weight (contents plus the
bag) of Fun Size Bags of M&Ms using the data collected in lab the first week of class.
The data are in the file M&MWeights_S13 on the course web page
(www.public.iastate.edu/~wrstephe/stat101L.html). Use JMP to analyze the distribution
of the Total Weight of bags. Use Analyze – Distribution with Total Weight in the
Y,Columns box. Include a stem and leaf plot for the distribution of Total Weight. Print
off a copy of the output and turn it in with your lab. Use the output to answer the
questions on the lab answer sheet.
Note: For the distribution of the Total Weight, JMP does not create a histogram that looks
like the ones we have seen in class. To get a more conventional histogram, choose a
Horizontal Display under Display Options (or Stack the Distribution). Add a vertical axis
label and scale by going to Histogram Options – Count Axis
Activity 2:
On the first day of class we talked about the heights of students in the class. In last weeks
lab we measured those heights, in cm. Now we will look at the heights and see if gender
can explain some of the variation in the heights of students. The data from last week’s
lab is on the course web site as a JMP data set called Height_S13.JMP. Open the JMP
data set and use JMP to analyze the distribution of height and the distribution of height by
gender. Be sure to follow the suggestions from previous labs, homework and class on
what should be included in the output and how the output should look. Turn in this
output with your lab.
1. Describe the distribution of heights of students in the class. Make sure to discuss
shape, center and spread and the presence of any outliers. Also, discuss the values
of the numerical summaries for this distribution and what they tell you about the
distribution. Recall that some numerical summaries, e.g. range, are not calculated
by JMP automatically but that you can get JMP to calculate them for you.
2. Discuss the similarities and differences you see in the distributions of heights of
male and female students. Again be sure to discuss shape, center and spread and
support your comparisons by referring to graphical and numerical summaries in
the JMP output.
3. What are some other variables that could account for variation in heights? How
could you investigate whether one of these other variables could account for
variation in heights?
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Statistics 101L – Laboratory 3 – Answer Sheet
Names: _______________________
_______________________
_______________________
_______________________
Activity 1:
1. Describe the shape of the distribution of total weight (bag plus contents) of Fun
Size bags of M&Ms. Explain briefly what about the Fun Size bag is influencing
the total weight and how this is represented in the histogram.
2. What are the values of the sample mean and sample median total weight? What
does the comparison of these values tell you about the shape of the distribution?
3. What are the values of the sample standard deviation and sample interquartile
range for the total weight?
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Activity 2
1. Describe the distribution of heights of students in the class and discuss the
values of the numerical summaries for this distribution and what they tell you
about the distribution.
2. Discuss the similarities and differences you see in the distributions of heights
of male and female students.
3. What are some other variables that could account for variation in heights?
How could you investigate whether one of these other variables could account
for variation in heights?
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