Thread: how to calculate SD or SEM of ratios?

1. how to calculate SD or SEM of ratios?

I have 2 groups of data. Group1: x1,x2,x3,x4. Group2:y1,y2,y3,y4. I want to
get the ratio of y over x (Y/X) and also needs to know the SD or SEM of the
ratio. How to calculate the SD or SEM of Y/X? In my data, I can use y1/x1,
or y1/x2 or y1/x3 or y1/x4. x1 is not only related to y1, but can also
related y2 or y3 or y4, (what i mean is I can also use y2/x1 or y3/x1 or y4/
x1)
Thanks!

2. Re: how to calculate SD or SEM of ratios?

Not familiar with this, but I am familiar with odds ratios. Never heard of SDs or SEM with ratios, though they may exist. The following is the formula for the standard errors of odds ratio. Also this can be used to calculate 95% confidence intervals.

3. Re: how to calculate SD or SEM of ratios?

Are X and Y independent?

4. Re: how to calculate SD or SEM of ratios?

Good question Dason. I believe what Dason is getting at may be if covariance may exist in their relationship.

 Tweet

Posting Permissions

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