정규분포 곡선을 간단하게 그린다.
graph처럼 표현하기 위해서 보정해준 부분들에 주의하자.
with st as (
select 0 mn, 9 sd from dual)
SELECT LPAD ('*', nd, '*') NDF
FROM (SELECT mn, sd,
1000
* EXP (-POWER ((LEVEL - 25 - mn) / sd, 2) / 2)
/ SQRT (2 * ACOS (-1))
/ sd nd
FROM st
CONNECT BY LEVEL <= 50)
*
*
**
**
***
****
*****
*******
*********
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*************
***************
******************
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*************************************
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*****************************************
****************************************
*************************************
***********************************
********************************
*****************************
**************************
***********************
*********************
******************
***************
*************
***********
*********
*******
*****
****
***
**
**
*
*