EXERCISE 1 - ANSWER

How much does a family's total school expenditure change with an increase in total monthly income and household food subsidy? Do these variables significantly explain/predict changes in total school expenditure? Why or why not?

For the answer to this questions, we will use the independent variables mxtsch (total school expenditure), totminc (total monthly income), and foodwage (household food subsidy). Also, we need to clean up the data, keeping only those observations where rel_head==1, and dropping all observations where our independent variables have either missing or invalid (< 0) values.

Once the data is cleaned up, enter the following in the Stata Command window:

reg mxtsch totminc foodwage

This results in the following table:

  Source |       SS       df       MS                  Number of obs =    4196
---------+------------------------------               F(  2,  4193) =   95.24
   Model |  6668804.88     2  3334402.44               Prob > F      =  0.0000
Residual |   146804937  4193  35011.9097               R-squared     =  0.0435
---------+------------------------------               Adj R-squared =  0.0430
   Total |   153473742  4195  36584.9207               Root MSE      =  187.11

------------------------------------------------------------------------------
  mxtsch |      Coef.   Std. Err.       t     P>|t|       [95% Conf. Interval]
---------+--------------------------------------------------------------------
 totminc |   .0076642   .0005622     13.632   0.000        .006562    .0087664
foodwage |  -.0828563    .041451     -1.999   0.046      -.1641221   -.0015904
   _cons |    40.3553   3.249525     12.419   0.000       33.98451    46.72609
------------------------------------------------------------------------------

Observing the coefficients for the independent variables totminc and foodwage, we can see that with a 1 Rand increase increase in total monthly income, a household will spend .007 Rand more on school expenditures. We can also see that, controlling for total monthly income, with a 1 Rand increase in food subsidy, a household will spend .08 Rand less on school expenditures. (Note that in this example, we have treated the variables as individual-level variables. Was this correct?? No, unless you purposely wanted to give larger households more weight in your answer.)

 

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