Stat 538 - Biostatistics I

Homework 4, due in Lab Thursday October 6


1. Problem 6.51 p. 215 in SW.  Get the summary statistics in Minitab, 
   construct the CI by hand, then confirm you get the same interval in
   Minitab.

2. 6.55 in SW p. 215.  Do by hand.

3. 6.58 in SW p. 216.  Do by hand.

4. 6.65 in SW p. 217.  Do by hand, then confirm you get the same
   interval in Minitab.

5. 6.66 in SW p. 217.

6. 6.67 in SW p. 217.  Do by hand, confirm your answer with Minitab.

7. Use the data from problem 1 in Homework 3.  Use Minitab to get 95% 
   CI's for mean birth weights of males and separately for mean birth 
   weights of females.  Given your answer to problem 1 in HW 3, do you 
   see difficulties with assumptions?  

   Interpret your intervals - what do they mean?

8. Use the data from problem 1 in HW 3 and use Minitab to produce a 
   95% CI for for the proportion of mothers who smoke during pregnancy.
   Use data manipulation methods to create an appropriate variable that
   shows if the mother smoked during pregnancy.  For the CI do not use 
   the summarized data option in Minitab.  You should get this interval 
   from "raw" data. (I want you to be able to deal with 10,000 cases 
   where you cannot easily count by hand).

   Interpret the interval.