Conditional Standard Deviation?

[PerthGuy]

Is it possible to create a formula (= ) for calculating the standard deviation with conditions, ie calculate only the values >-2 and <2 in a data set?

 

[Aladin Akyurek]

On 2002-03-06 01:56, PerthGuy wrote:
Is it possible to create a formula (= ) for calculating the standard deviation with conditions, ie calculate only the values >-2 and <2 in a data set?

Array-enter:

=STDEV(IF((A1:A100>-2)*(A1:A100<2),A1:A100)

where A1:A100 houses the values of interest.

To array-enter a formula, you need to hit control+shift+enter at the same time, not just enter.

Aladin

 

[Dave Hawley]

Hi PerthGuy

Perth WA ?


Array formulas can have an adverse effect on Excel re-calculations. Personally I would use the:

DSTDEV Function

All the DFunctions work off the same pricipal and the Excel help on them is very good. Just type Database functions into the help. These functions are designed to work with large data tables are are far quicker.

I also have examples an ideas for these great functions here:

http://www.ozgrid.com/download/default.htm

under:

DFunctionsWithValidation.zip

 

[PerthGuy]

Thanks Aladin and Dave.

Aladin's suggestion works fine, however I have another question: I want to be able to remove data from column A and replace it with either more or less data. this means I have to keep adjusting the formula to suit, ie from A1:A10 to A1:A20; or from A1:A20 to A1:A15, etc. I have tried naming the column by clicking on the A at the top, and using the name (Data) as a reference, but I keep getting a #DIV/0! message. Any suggestions?

Here is what my formula looks like:

{=STDEV(IF((Data>-0.5)*(Data<0.5),Data))}

 

[Dave Hawley]

Hi PerthGuy

I will leave this to Aladin as I honestly think you are heading down the wrong track and I don't do that to people! If you would like some help the Dfunctions I am more than willing to help. I

 

[Aladin Akyurek]

On 2002-03-06 22:05, PerthGuy wrote:
Thanks Aladin and Dave.

Aladin's suggestion works fine, however I have another question: I want to be able to remove data from column A and replace it with either more or less data. this means I have to keep adjusting the formula to suit, ie from A1:A10 to A1:A20; or from A1:A20 to A1:A15, etc. I have tried naming the column by clicking on the A at the top, and using the name (Data) as a reference, but I keep getting a #DIV/0! message. Any suggestions?

Here is what my formula looks like:

{=STDEV(IF((Data>-0.5)*(Data<0.5),Data))}

Lets say that column A from A1 on houses the values of interest.

In B1 enter:

=MATCH(9.99999999999999E+307,A:A)

In B2 enter: -0.5
In B3 enter: 0.5
In B4 array-enter:

=STDEV(IF((OFFSET($A$1,0,0,$B$1,1)>$B$2)*(OFFSET($A$1,0,0,$B$1,1)<$B$3),OFFSET($A$1,0,0,$B$1,1)))

Aladin

 

[Ivan F Moala]

On 2002-03-06 22:21, Dave Hawley wrote:
Hi PerthGuy

I will leave this to Aladin as I honestly think you are heading down the wrong track and I don't do that to people! If you would like some help the Dfunctions I am more than willing to help. I

Dave, an array formula in this situation
may be advisable aslong as he dosen't
have a book full of these and UDF's....that
will take up excels calculation engine time.

Ivan

 

[Dave Hawley]

You are right in the repsect that a couple wont hurt. But It's very unlikely (once a unwary user) discovers then they will stop at one. Besides I believe if we are going to help somebody we should do it properly and not give a short term solution.

 

[PerthGuy]

Aladin,

Success. Thank you for your help.

Dave,

Yes, I'm from Perth, WA. Where are you located?

Thank you for your assistance. I would like to learn about the Dfunctions sometime, but Aladin's solution works fine for this particular work I'm doing. But I have Bookmarked the web site you suggested for when I need to do this.

I do, however, have another question out of curiosity: Is it possible to separate the data from col A into two columns, ie <0 in col A, >0 in col B?

 

[PerthGuy]

Aladin,

Success. Thank you for your help.

Dave,

Yes, I'm from Perth, WA. Where are you located?

Thank you for your assistance. I would like to learn about the Dfunctions sometime, but Aladin's solution works fine for this particular work I'm doing. But I have Bookmarked the web site you suggested for when I need to do this.

I do, however, have another question out of curiosity: Is it possible to separate the data from col A into two columns, ie <0 in col A, >0 in col B?