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

SELECT array_to_kurtosis('{1,1,5,2,0}'::smallint[]);
 array_to_kurtosis  
--------------------
 2.6519357195032867
(1 row)

SELECT array_to_kurtosis('{1,1,5,2,0}'::integer[]);
 array_to_kurtosis  
--------------------
 2.6519357195032867
(1 row)

SELECT array_to_kurtosis('{1,1,5,2,0}'::bigint[]);
 array_to_kurtosis  
--------------------
 2.6519357195032867
(1 row)

SELECT array_to_kurtosis('{1,1,5,2,0}'::real[]);
 array_to_kurtosis  
--------------------
 2.6519357195032867
(1 row)

SELECT array_to_kurtosis('{1,1,5,2,0}'::float[]);
 array_to_kurtosis  
--------------------
 2.6519357195032867
(1 row)

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