STA 3024                                            Project 1                                             Spring 2006

                                                           

 

Worth:             30 points

 

Project Due:    Wednesday, March 8, 2006, at 4pm.  Turn it in during class, or in my mailbox in Griffin Floyd 103.  The mailbox is the one UNDER the label Ripol.  Late Projects will be accepted until Friday, March 10, in class, but will result in a 10-point penalty.

 

Purpose:        To study the relationship between height and weight of UF students and learn how to perform Simple Linear Regression using Minitab.

 

 

1.  Collect the data

You need to collect data on the height, weight and gender of 10 UF students.  Explain to the participants what the data will be used for.  The data should be treated confidentially. 

 

You may collect data on yourself, you friends, classmates, or students that you don’t know.  This is NOT a random sample, but it would be quite difficult to do it at random.  Each student in the class should have a different set of participants, and later we will pool all the data you collect with that of the other students in the class.  It is important to ask your participants if they have already provided their information to any other students in the class.  In that case you will not be able to use their information, and will need to find another participant.

 

A template for the data collection form is provided below.  You should cut the slips beforehand, and bring an envelope with you, so that participants can place the slips in the envelope without anyone else handling them.

 

2.  Get ready to use Minitab – you can buy it, rent it, download it for free (30 days) or use it in the CIRCA Labs.  See course website for more details.  I have requested a reservation for one of the CIRCA lab classrooms (CBD 110) for Thursday 3/2, 4th-5th periods and Tuesday, 3/7, 7th and 8th periods.  Please check course website for confirmation of these times.  Yun Zhu, the TA for our class, will be there to help people who need it. 

 

3.  Enter the data into Minitab- creating a column for gender (male or female), a column for height (in inches) and a column for weight (in pounds).  The column names go on the very top row.  The data for each subject goes into one row.  You should have data in three columns and 10 rows. 

Note:  The column identifiers C1, C2, etc, change to C1-T, C2-T, etc, if the data in them is text.  The only column that should be identified as text is gender.  The height and weight columns should be numerical.  If you accidentally write any text in them you will need to re-enter the data using new columns.

 

 

4.  Perform the regression analysis –

a.       On the top menu, go to Stat – Regression – Fitted Line Plot

b.      Select weight for response (y) and height for predictor (x).

c.       Make sure that Linear is selected.

d.      Click OK

 

 

5.  Prepare your report using a word processor.  The report should be 2 pages long, and include the following (see example on last page):

 

a.      Your NAME and UFID number, and the course information.

b.      The data you used (5pts)– with the left mouse button, select the three columns of data from the spreadsheet, then use the “copy” function in Minitab, and paste it into your document. 

c.       The plot created by Minitab (5pts)– using the mouse, right-click on the graph, select “Copy Graph” and paste it into your document.

d.      The Regression Analysis created by Minitab (5pts)–  with the left mouse button, select the text that appears on the Session window, then use the “copy” function in Minitab, and paste it into your document.

e.      A brief interpretation of the slope, intercept and R2 of the line. (6 pts)

f.        A brief interpretation of the results of the ANOVA test. (4 pts)

g.      STAPLE your report – no paper clips, tape, crimped pages, etc.  (5 pts)

 

Note:  If the “cut” and “paste” functions do not work with your word processor, you may print the computer output, and NEATLY write the interpretations.

 

 

 

 

 

 

TO OUR PARTICIPANTS:

 

1.      This is a confidential and voluntary survey.

 

2.      We are collecting data for our STA 3024 class project to study the relationship between height and weight for UF students.

 

3.      You should only participate ONCE – if you have already provided your information to another student in the class, I cannot use it.

 

4.      Please write down your information on the spaces provided.  Then fold the paper and place it in the envelope.

 

5.      Thank you very much for participating.

 

 

 

Gender:  Male / Female (circle one)

Weight:   __________      in pounds

Height:    __________      in inches    

Note: 5 ft = 60”   6 ft = 72”

 

 

Gender:  Male / Female (circle one)

Weight:   __________      in pounds

Height:    __________      in inches    

Note: 5 ft = 60”   6 ft = 72”

 

 

Gender:  Male / Female (circle one)

Weight:   __________      in pounds

Height:    __________      in inches    

Note: 5 ft = 60”   6 ft = 72”

 

 

Gender:  Male / Female (circle one)

Weight:   __________      in pounds

Height:    __________      in inches    

Note: 5 ft = 60”   6 ft = 72”

 

 

Gender:  Male / Female (circle one)

Weight:   __________      in pounds

Height:    __________      in inches    

Note: 5 ft = 60”   6 ft = 72”

 

 

Gender:  Male / Female (circle one)

Weight:   __________      in pounds

Height:    __________      in inches    

Note: 5 ft = 60”   6 ft = 72”

 

 

Gender:  Male / Female (circle one)

Weight:   __________      in pounds

Height:    __________      in inches    

Note: 5 ft = 60”   6 ft = 72”

 

 

Gender:  Male / Female (circle one)

Weight:   __________      in pounds

Height:    __________      in inches    

Note: 5 ft = 60”   6 ft = 72”

 

 

Gender:  Male / Female (circle one)

Weight:   __________      in pounds

Height:    __________      in inches    

Note: 5 ft = 60”   6 ft = 72”

 

 

Gender:  Male / Female (circle one)

Weight:   __________      in pounds

Height:    __________      in inches    

Note: 5 ft = 60”   6 ft = 72”

 

 

 

Jane Doe                                                                                            STA 3024 Fall 2004

UFID 1234-5678                                                                                Project 1

 

Data collected:

 

gender  ht         wt

m         69        175

f           62        110

f           68        140

m         72        199

m         67        184

f           64        160

m         70        215

f           59        98

m         66        144

m         76        228

 

 

 

 

Results:

 

 

 

 

 

Minitab Output:

 

The regression equation is

wt = - 367.9 + 7.923 ht

 

 

S = 19.3572   R-Sq = 82.0%   R-Sq(adj) = 79.8%

 

 

Analysis of Variance

 

Source      DF       SS       MS      F      P

Regression   1  13692.5  13692.5  36.54  0.000

Error        8   2997.6    374.7

Total        9  16690.1

 

 

 

 

Interpretations:

 

Slope:  As the height of UF students increases by one inch, weight increases by 7.923 pounds, on average.

 

Intercept:  Since a height of 0 inches is impossible, we do not interpret the intercept.

 

R2:  82.0% of the variability in UF student’s weight is explained by their height.

 

 

ANOVA test:  Since the p-value was reported as .000, we conclude that height is a good predictor of weight.