Use your browser to download your data from the following link;
http://www.palmx.org/drtamil/2018/Mei18/matricno.dta
If your matric number is P20627, then download your data from;
http://www.palmx.org/drtamil/2018/Mei18/P020627.dta
Do the following analysis on the data then submit your answers via this LINK.
A study to identify factors that can cause small for gestational age (SGA) was conducted. Among the factors studied were the mothers’ body mass index (BMI). It is believed that mothers with lower BMI were of higher risk to get SGA babies.
1. Create a new variable mBMI (Mothers’ Body Mass Index) from the mothers’ HEIGHT (in metre) & WEIGHT (first trimester weight in kg). mBMI = weight in kg/(height in metre)2. Calculate the following for mBMI;
Copy and paste your answers into your Word file.
2. Create a new variable OBESCLAS (Classification of Obesity) from mBMI. Use the following cutoff point;
- <20 = Underweight
- 20 – 24.99 = Normal
- 25 or larger = Overweight
Copy and paste these commands into the STATA command window
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gen OBESCLAS = 1 if mBMI< 20
replace OBESCLAS =2 if (mBMI >= 20 & mBMI< 25)
replace OBESCLAS =3 if mBMI >= 25.00
label variable OBESCLAS “Classification of Obesity”
label define OBESCLAS 1 “Underweight” 2 “Normal” 3 “Overweight”
label values OBESCLAS OBESCLAS
tabulate OBESCLAS, miss
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Create a frequency table for OBESCLAS. Copy and paste the table into your Word file.
3. Conduct the appropriate statistical test to test whether there is any association between OBESCLAS (Underweight/Normal/Overweight) and OUTCOME.
Copy and paste the appropriate tables along with the interpretation into your Word file.
4. Conduct the appropriate statistical test to test whether there is any association between BMI and OUTCOME.
Copy and paste the appropriate tables along with the interpretation into your Word file.
5. Conduct the appropriate statistical test to find any association between OBESCLAS (Underweight/Normal/Overweight) and BIRTHWGT.
Copy and paste the appropriate tables along with the interpretation into your Word file.
6. Assuming that both variables mBMI & BIRTHWGT are normally distributed,
- conduct an appropriate statistical test to prove the association between the two variables.
- Demonstrate the association using the appropriate chart. Determine the coefficient of determination.
Copy and paste the above charts and your answers into your Word file.
7. Conduct Simple Linear Regression using BIRTHWGT as the dependent variable. Try to come out with a formula that will predict the baby’s birthweight based on the mother’s BMI.
y = a + bx
8. Download MLR.dta from http://www.palmx.org/drtamil/2018/Mei18/MLR.dta and analyse using MLR with STATA. The outcome of interest is cholesterol level. The risk factors are Age, Diet, Exercise and Socioeconomic Status. Type the preliminary main effect model (y=a+bx) in the answer box.
Copy and paste the appropriate tables and supporting chart along with the interpretation into your Word file.
Save your Word file using your matric number as its filename i.e. P20627.doc. Now transfer your answers from the Word file onto this online form at LINK. Upon finishing, please click the SUBMIT button to submit your answers.
Just in case your answers go missing in the ethers of cyberspace, please email the above Word document file ( e.g. P20627.doc) to statsexam@gmail.com, using your matric number (i.e. P20627) as its’ subject header.
Biostatistics and Epidemiology 