SELECT array_to_mean('{}'::float[]);
 array_to_mean 
---------------
              
(1 row)

SELECT array_to_mean('{1,1,5,2,0}'::smallint[]);
 array_to_mean 
---------------
           1.8
(1 row)

SELECT array_to_mean('{1,1,5,2,0}'::integer[]);
 array_to_mean 
---------------
           1.8
(1 row)

SELECT array_to_mean('{1,1,5,2,0}'::bigint[]);
 array_to_mean 
---------------
           1.8
(1 row)

SELECT array_to_mean('{1,1,5,2,0}'::real[]);
 array_to_mean 
---------------
           1.8
(1 row)

SELECT array_to_mean('{1,1,5,2,0}'::float[]);
 array_to_mean 
---------------
           1.8
(1 row)

SELECT array_to_mean('{1,1,5,2,0}'::text[]);
ERROR:  Mean subject must be SMALLINT, INTEGER, BIGINT, REAL, or DOUBLE PRECISION values