|Member 2||: _______________________________|
|Member 3||: _______________________________|
|Hospital #||: ________________|
|Random Seed||: ________________|
There are "truths" that everyone knows and believes. For instance, everyone knows that "there are more births on a full moon." I recently mentioned the birthrate during a full moon to a friend who promptly replied "I know that's true. It's been proven."
"Urban Legends", "Old wives tales", call it what you will, there are many things that we know to be true without any statistical evidence to support that claim. That's statistical ignorance and it's what we're going to be examining this semester for our semester project. We're going to take one of the claims that we've heard and see whether or not there is any statistical basis for the claim.
The Skeptics Dictionary has this to say about full moons and other lunar effects. "The full moon has been linked to crime, suicide, mental illness, disasters, accidents, birthrates, fertility, and werewolves, among other things."1 I'll stop there, although there is more information online. We're going to collect data on births of children and see if there is any correlation between birth rates and the phase of the moon.
The instructor will divide the class into groups of about three students each based on criteria such as availability and computer expertise. Each group will be assigned a hospital from Central Illinois from which to collect birth information.
Most of the computer work can be done in class, but there may be some times that the groups will have to meet outside of class, so the instructor tries to group people based on open times.
The hospitals leave the information on their web sites for at least a month (some up to six months), so this is not something that you will have to check every day, but it is something that you should check at least every couple of weeks. There is usually a delay of a few days to a week before new information is posted.
We will be collecting data for all of January, February, and March 2002.
The student should not expect classroom time to collect the data. However, there should be sufficient time immediately prior to or following class to collect the data. The information can be entered into SPSS in either the S137 classroom or the C239 computer lab.
Each group will enter their data into a separate file and the instructor will combine the information into a single file for the steering committee to use in the next phases of the project. The instructor will create a blank template file for you called "master.sav". This file will be located on the acad1 fileserver under the location "\\acad1\stats\01\births" When you choose "open" in SPSS, type in "\\acad1\stats\01\births" and then you should see the file. Before entering your data, use the File / Save As command to save this file as "hosp#" where "#" is the number of your hospital. This should only be done once and then all subsequent data entry should be done with this file. Caution! Only one student may access the data file at a time for editing purposes. More than one student may open the file for use, but you should not make changes while other students have the file open. You will get a warning about the file being in use if you try this.
There will be a syntax file that contains the commands for computing the computed variables. The students may run that on their data file at any time, it will not destroy existing data. The name of the syntax file will be "births.sps" and it will be located in the "\\acad1\stats\01\births" directory on the fileserver. To open this file, choose File / Open / Syntax from the menu. It should default to the same directory as the last opened data file, so you should be in the right place.
To execute the syntax file and compute the remainder of the data, choose Run / All from the syntax file window. Save your data file after running the syntax file. Do not save changes to the syntax file.
For your hospital only, answer the following questions. Annotate the output so that each section is clearly labeled and add text to describe any interesting comments. The SPSS command sequence is given to get you started in the right direction.
Use the combined class data to answer the following questions. The combined classroom data will be in the file "births.sav" in the "\\acad1\stats\01\births" directory on the fileserver.
Since large sample sizes can make even the smallest differences significant, restrict your sample to a subset of the entire file. Set the random seed to the birthdate of the youngest member of your group in mmddyy format. For example, if the youngest person in your group was born on July 17, 1982, then you would enter 071782 for the random seed. The random seed can be found under Transform / Random Number Seed. This will guarantee that you will get the same random sample each time you do the analysis (so you can come back in case you don't get it all done the first time) and it will also give different responses for each group so we can look at different samples. Write the random number seed on the front sheet for future reference.
After you have set the random seed (you need to do this each time you open SPSS), randomly select approximately the given percent of cases. To do this, go to Data / Select Cases / Random sample of cases and enter a percent of the total sample size to randomly select. Each question has its own percent to sample. The sample sizes are based on the assumption of approximately 450 births per month between the eight hospitals for three months of data.
Answer the following questions. Be sure to annotate your output so the questions are clearly identified and the answers to the questions are given.
Project Evaluation (10 points)
As a group, comment on the entire project. As a minimum, address questions like
This should be typed and only one document per group submitted.
Individual Evaluations (10 points)
As an individual, evaluate each member of your group including yourself. Comment on how much they contributed to the group. Did they show up for all the meetings, did they participate when they showed up, did they pull their weight or did they not do anything.
In addition to a paragraph describing each person, assign them a score between 0 and 10 points for their effort in the group. Remember you are evaluating yourself, also.
The score that you receive for this part of the project will be the mean scores given to you by each person in your group. This may be handwritten and there should be one document per person.
The following hospitals will be used. The Hospital ID (used in "collected data" section) precedes each hospital name. The larger hospitals from surrounding areas have been chosen.
|hosp||:||Hospital ID (see above)|
|date||:||Date of birth (month, day, year)|
|time||:||Time of birth|
|sex||:||Gender of child (1=Boy, 2=Girl)|
|length||:||Length of child (in inches)|
|lbs||:||Weight in pounds|
|oz||:||Weight in ounces|
* This information won't be analyzed, it is collected only for the purpose of identifying the baby so the information isn't entered more than once. The parents' name(s) can be used to determine if there is a single parent listed for the single variable.
The following information will be computed. You do NOT need to record it as you enter the birth information into SPSS.
|city||:||City (computed from hosp, 1=Bloomington, 2=Decatur, 3=Peoria, 4=Springfield)|
|weight||:||Combined weight in pounds (computed from lbs and oz)|
|phase||:||Lunar phase (computed from the date, 1=New, 2=Waxing Crescent, 3=1st Quarter, 4=Waxing Gibbous, 5=Full, 6=Waning Gibbous, 7=3rd Quarter, 8=Waning Crescent). See http://www.googol.com/moon/ for more information.|
|moon||:||Lunar days (Computed from the date and time, 1=New, 2=1stQuarter, 3=Full, 4=3rd Quarter)|
|wkday||:||Day of week (computed from the date, 1=Sun, 2=Mon, ..., 7=Sat)|