* t-test on OLS Model for Food Expenditure in India
*
* Keywords:
*     regression, ols, t-test, food, expenditure, India, histogram
*
* Description:
*     We illustrate how to do a t-test on an estimated Linear OLS Model for 
*     Food Expenditure in India and plot a histogram of residuals
*
* Author(s):
*     Skif Pankov
*
* Source:
*    Damodar N. Gujarati and Dawn C. Porter, Basic Econometrics - 5th Edition
*    McGraw-Hill International Edition, Chapter 5, Example 5.1 (page 133)
*
sample 1 55

* Read the datafile and name the variables
read (data_3.2.shd) foodexp totalexp

* Running an OLS regression of foodexp on totalexp, specifying to display 
* residual statistics and to save the residuals in the variable resids
ols foodexp totalexp / rstat resid = resids

* Constructing a t-test with a null hypothesis that the coefficient of 
* totalexp is equal to 0.5
test totalexp = 0.5

* Plotting a histogram of residuals with 15 groups
graph resids / histo groups=15

stop