This handout includes both an ANOVA and a regression printout for Problem
3 from the midterm.  Recall that the investigator was collecting pollution
measurements at elementary schools in 5 locations:  in the
parking (P) lot at morning drop-off, in the play yard at afternoon recess
(R), in the cafeteria (C) at lunch time, and in two classrooms right
before lunch, one with the windows closed and air conditioner running (A)
and one with the windows open (W).

. oneway particle location, tabulate bonferroni

                |         Summary of particle
       location |        Mean   Std. Dev.     Freq.
 ---------------+------------------------------------
 A (class, AC)  |        14.2      7.1         25
 C (cafeteria)  |        19.1      6.9         25
 P (parking lot)|        37.9      6.7         25
 W (window open)|        36.8      5.1         25
 R (play yard)  |        41.5      9.0         25
----------------+------------------------------------
          Total |        29.9     13.1        125

                        Analysis of Variance
    Source              SS      df       MS         F   Prob > F
-----------------------------------------------------------------
Between groups      15225.6      4   3806.4     76.13     0.0000
 Within groups       6000.0    120     50.0
-----------------------------------------------------------------
    Total           21225.6    124    171.2


. regress particle parkinglot windowopen cafeteria aircon

      Source |       SS       df       MS              Number of obs =     125
-------------+------------------------------           F(  4,   120) =   76.13
       Model |    15225.6     4    3806.4              Prob > F      =  0.0000
    Residual |     6000.0   120      50.0              R-squared     =  0.7173
-------------+------------------------------           Adj R-squared =  0.7079
       Total |  21225.5816   124  171.174046           Root MSE      =  7.0711

------------------------------------------------------------------------------
    particle |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
  parkinglot |  -3.626978          2    -1.81   0.072    -7.586838    .3328833
  windowopen |  -4.746978          2    -2.37   0.019    -8.706838   -.7871167
   cafeteria |  -22.42698          2   -11.21   0.000    -26.38684   -18.46712
      aircon |  -27.30698          2   -13.65   0.000    -31.26684   -23.34712
       _cons |   41.50698   1.414214    29.35   0.000     38.70693    44.30702
------------------------------------------------------------------------------