Lab-session 2:
1. use lab1.dta; change to your preferred working directory and then open a log file for the
work session:
cd: c:\...
log using name.log
2. look at histograms and density plots for all variables in the variable list
kdensity y
histogram y
etc.
3. test all variables of normality, kurtosis and skewness and interprete the results.
swilk y
sktest y
etc.
4. run one-sample ttest for all variables, use null hypotheses of your own choice:
ttest y=4
etc.
5. compare the mean and standard deviations of different pairs of variables and interpret the
results.
ttest x1=x2
sdtest x5=x6
etc.
6. compare the means and standard deviations of sub-groups of variables by using x9 as a
treatment variable:
ttest x1, by(x9)
ttest x1, by(x9) unequal
sdtest x5,by(x9)
etc.