ExampleHere there are two questions:
- S8: How many patients do you treat?
- Q1: How many patients do you treat with a Gamma Agonist?
|1 to 10||16|
|11 to 25||31|
|26 to 50||35|
|51 to 100||16|
|1 to 10||67|
|11 to 25||19|
|26 to 50||6|
|51 to 100||2|
Calculate ratios of elements
Clone Q1 to create a new element (see this brief tutorial on cloning). Let's call it Q1vS8. You don't have to clone it but you may want to see both the original counts and the ratio.
For this new element, select press the circle edit icon and choose "More properties..." from the context menu. Then under "Denominator" enter "S8" and press Ok.
Voilá! You now have a new element that is defined as Q1 / S8.
|1 to 20||40|
|21 to 40||23|
|41 to 60||12|
|61 to 80||13|
|81 to 100||7|
Note in this example we also set the Scale to 100 in the "More Properties..." menu. As an analyst you may be familiar seeing percentages in the interval of 0 to 1. But your client may prefer to see ratio on an interval of 0 to 100.
Means are ratio averages
When you use the Denominator property, the mean is intelligently weighted to show the ratio average, i.e. the sum of numerators over sum of denominators, excluding rows with missing values for either. You can verify this yourself, as 12.1 / 36.9 x 100 = 32.8.