The following are the dosage of medicine and blood AZT concentration levels of 32 healthy adult males


Dosage


2.5


2.5


2.5


2.5


2.5


1.9


2.1


1.9


1.9


0.9


1.5


1.4


1.4


1.5


1.8


1.8



2.0


1.8


0.9


0.6


0.9


1.3


1.1


1.4


1.1


0.8


0.7


1.0


1.1


0.8


1.0


0.9



concentration


832


672


904


554


996


878


815


805


592


391


710


591


660


694


668


601



77l


757


213


394


391


430


440


352


337


181


174


470


426


170


360


320




1. Describe the above variables using both numerical and graphical methods.
2. Make a stem and leaf display for each variable and use it to describe the each variable’s distribution.
3. Use z-scores to determine if the minimum and maximum values of the variable AZT concentration are outliers.
4. Make a scatter plot of the two variables. Use the scatter plot to describe the form of the relationship (if any) between the two variables.
5. Predict the AZT concentration level of a healthy adult male who received a medicine dosage = 2.2. How accurate is your prediction ?
6. Find the correlation coefficient between the dosage of medicine and blood AZT concentration level.
7. Construct the 95 % confidence interval for the mean of blood AZT concentration level.
8. Is there enough evidence at the a = 0.5 significance level that the mean of blood ZT is greater than 450?