\qecho =================================================================
\qecho === Running: mulit-linear regression ============================
\qecho =================================================================
\qecho 
\qecho === Refresh table: houses =======================================

DROP TABLE IF EXISTS houses;
CREATE TABLE houses (id INT, tax INT, bedroom INT, bath FLOAT, price INT, size INT, lot INT) distributed by (ID);

COPY houses FROM STDIN DELIMITER '|';
  1 |  590 |       2 |    1 |  50000 |  770 | 22100
  2 | 1050 |       3 |    2 |  85000 | 1410 | 12000
  3 |   20 |       3 |    1 |  22500 | 1060 |  3500
  4 |  870 |       2 |    2 |  90000 | 1300 | 17500
  5 | 1320 |       3 |    2 | 133000 | 1500 | 30000
  6 | 1350 |       2 |    1 |  90500 |  820 | 25700
  7 | 2790 |       3 |  2.5 | 260000 | 2130 | 25000
  8 |  680 |       2 |    1 | 142500 | 1170 | 22000
  9 | 1840 |       3 |    2 | 160000 | 1500 | 19000
 10 | 3680 |       4 |    2 | 240000 | 2790 | 20000
 11 | 1660 |       3 |    1 |  87000 | 1030 | 17500
 12 | 1620 |       3 |    2 | 118600 | 1250 | 20000
 13 | 3100 |       3 |    2 | 140000 | 1760 | 38000
 14 | 2070 |       2 |    3 | 148000 | 1550 | 14000
 15 |  650 |       3 |  1.5 |  65000 | 1450 | 12000
\.

\qecho === Show data sample: ===========================================
select * from houses limit 5;

\qecho === Calculate Coefficients ======================================
select madlib.linregr_coef(price, array[1, bedroom, bath, size])::REAL[] from houses;

\qecho === Calculate R square value ====================================
select madlib.linregr_r2(price, array[1, bedroom, bath, size])::REAL from houses;

\qecho === Calculate t statistics ======================================
select madlib.linregr_tstats(price, array[1, bedroom, bath, size])::REAL[] from houses;

\qecho === Calculate p values ==========================================
select madlib.linregr_pvalues(price, array[1, bedroom, bath, size])::REAL[] from houses;