1. Registered User
Join Date
Jun 2003
Location
New York
Posts
5

Hello everyone.
My first time posting here! I have recentl been computing the geometric mean of a column in out Swl Server 200 Db using the following script:
@PE_Geo = exp(avg(log(PE1)))

this has worked greate, however I need to change this to the harmonic mean. Anyone have any ideas on the cimplest way to do this.

A simple example of the harmonic mean:
If you want the harmonic mean of 10 and 20, you first
take 1/10 and 1/20, find their average, which is 3/40, and then take
the reciprocal of that, 40/3.

In algebra, the harmonic mean h of two numbers a and b is

1 / ( (1/a + 1/b) / 2),

or in other words

1/m = 1/2 (1/a + 1/b).

Thanks for any help!

2. World Class Flame Warrior
Join Date
Jun 2003
Location
Ohio
Posts
12,595
select 1/(sum(1/[value])/count([value]))

You made need to cast your value as a different datatype to prevent rounding errors.

blindman

3. Registered User
Join Date
Jun 2003
Location
New York
Posts
5
Originally posted by blindman
select 1/(sum(1/[value])/count([value]))

You made need to cast your value as a different datatype to prevent rounding errors.

blindman
Thank you!
Float ok?

4. World Class Flame Warrior
Join Date
Jun 2003
Location
Ohio
Posts
12,595
Depends on your data. Float and Real are approximate values, and I don't know how they might propogate errors. Numeric and Decimal are more accurate, but you must define their accuracy ahead of time.

blindman

5. Registered User
Join Date
Jun 2003
Location
New York
Posts
5
Thanks again...
BTW: Have an experts-exchange account: 100pts!

http://www.experts-exchange.com/Data..._20704165.html

6. World Class Flame Warrior
Join Date
Jun 2003
Location
Ohio
Posts
12,595
I've thought about joining Experts Exchange, but what would I do with the 100 points? Can I trade them in for a toaster?

blindman

7. Registered User
Join Date
Jun 2003
Location
New York
Posts
5
Hehe...

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•