/* Read in data for problem #2, chapter 8, p. 127 */
capture clear
input byte patient byte y x1 x2
 1   44   2.80   6.10
 2   25   3.10   5.10
 3   10   2.59   6.00
 4   28   3.36   6.90
 5   25   2.80   7.00
 6   72   3.35   5.60
 7   45   2.99   6.30
 8   25   2.99   7.20
 9   12   2.92   6.90
10   24   3.23   6.50
11   46   3.37   6.80
12    8   2.72   6.60
13   15   3.47   8.40
14   28   2.70   5.90
15   26   3.24   6.00
16   27   2.65   6.00
17    4   3.41   7.60
18   14   2.58   6.20
19   21   2.81   6.00
20   22   2.80   6.40
21   60   3.62   6.80
22   10   2.74   8.40
23   60   3.27   6.70
24   12   3.78   8.30
25   28   2.90   5.60
26   39   3.70   7.30
27   14   3.40   7.00
28    8   2.63   6.90
29   11   2.65   5.80
30    7   3.26   7.20
31   23   3.15   6.50
32   16   2.60   6.30
33   26   2.74   6.80
34    8   2.72   5.90
35   11   3.11   6.80
36   12   2.79   6.70
37   50   2.90   6.70
38    9   2.74   5.50
39   13   2.70   6.90
40   22   3.08   6.30
41   23   2.18   6.10
42   31   2.88   5.80
43   20   3.04   6.80
44   65   3.32   7.30
45    9   2.80   5.90
46   12   3.29   6.80
47   21   3.56   8.80
48   13   2.74   7.10
49   10   3.06   6.90
50    4   2.54   6.70
51   18   2.78   7.20
52   10   2.81   5.20
53    7   3.26   6.60
end

label variable y  "Level of Pathology"
label variable x1 "Pretreatment Symptom Ratings--Thinking Disturbance"
label variable x2 "Hostile Suspiciousness"
format x1 x2 %9.2f


/* Chapter 8, problem #2a, p. 128 */
quietly {
  reg y x1 x2
  local x1h=2.8
  local x2h=7.0
  local pred=_b[_cons]+(_b[x1]*`x1h')+(_b[x2]*`x2h')
  local actual=y[5]
  noisily di _n _col(2) "Chapter 8, problem 1a, p. 128"
  noisily di    _col(4) "Y for case #5=" `actual' "; the predicted value=" %5.2f `pred'
}


/* Chapter 8, problem #2b, p. 128 */
quietly {
  reg y x1
  local r21=e(r2)

  reg y x2
  local r22=e(r2)

  reg x1 x2
  local r23=e(r2)

  #delimit ;
    noisily di _n _col(2) "Chapter 8, problem 1b, p. 128"
               _n _col(4) "r2;  Y|X1=" %6.4f `r21'
               _n _col(4) "r2;  Y|X2=" %6.4f `r22'
               _n _col(4) "r2; X1|X2=" %6.4f `r23'
    ;
  #delimit cr
}