Home |
Search |
Today's Posts |
#1
|
|||
|
|||
Pivot tables and Standard Deviation
I have columns of data that decrease in value that I collate using a pivot
table. Table Object Run Time Mass 100 0 36.1791 100 1 36.1709 100 2 36.1617 100 3 36.1527 100 4 36.1449 100 5 36.1367 100 6 36.1292 100 7 36.1209 100 8 36.1138 101 0 36.2029 101 1 36.1931 101 2 36.1837 101 3 36.1756 101 4 36.1682 101 5 36.1604 101 6 36.153 101 7 36.1455 101 8 36.1373 102 0 34.5683 102 1 34.5598 102 2 34.5515 102 3 34.5439 102 4 34.5366 102 5 34.5285 102 6 34.5215 102 7 34.5142 102 8 34.5066 After setting up the pivot table with 'Mass' as the target, I double click the 'Count of Mass' and modify the table to my needs. ie Average, StdDev and so forth. Using the "PivotTable Field" -options I selected Difference from (previous) for in this particular case "Run Time". Problem. If I use the StdDev function I get negative numbers showing up in the table. Since standard deviation is by definition the root of a square, I find the result disturbing not to mention a little disconcerting for my research since I have been depending on Excel for other number crunching statistics. What is going on? Tom |
#2
|
|||
|
|||
Pivot tables and Standard Deviation
Hi tom,
You are seeing the difference of StdDev(at RunTime t) from StdDev(at RunTime t-1), so yes you will get negative numbers. Ed Ferrero http://edferrero.m6.net/ I have columns of data that decrease in value that I collate using a pivot table. Table Object Run Time Mass 100 0 36.1791 100 1 36.1709 100 2 36.1617 100 3 36.1527 100 4 36.1449 100 5 36.1367 100 6 36.1292 100 7 36.1209 100 8 36.1138 101 0 36.2029 101 1 36.1931 101 2 36.1837 101 3 36.1756 101 4 36.1682 101 5 36.1604 101 6 36.153 101 7 36.1455 101 8 36.1373 102 0 34.5683 102 1 34.5598 102 2 34.5515 102 3 34.5439 102 4 34.5366 102 5 34.5285 102 6 34.5215 102 7 34.5142 102 8 34.5066 After setting up the pivot table with 'Mass' as the target, I double click the 'Count of Mass' and modify the table to my needs. ie Average, StdDev and so forth. Using the "PivotTable Field" -options I selected Difference from (previous) for in this particular case "Run Time". Problem. If I use the StdDev function I get negative numbers showing up in the table. Since standard deviation is by definition the root of a square, I find the result disturbing not to mention a little disconcerting for my research since I have been depending on Excel for other number crunching statistics. What is going on? Tom |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
How to compare two tables in Access 2000? | Excel Discussion (Misc queries) | |||
Pivot tables design | Excel Worksheet Functions | |||
Help with Charting My Data -- | Charts and Charting in Excel |