# How to compute the standard error with only sample size, mean of percentage and interquartile range?

#### sherlockyin

##### New Member
I have a percentage which is the rate of reduction. For example, each patient was measured on a scale several times, and the reduction rate was computed by (time 2-time 1)/time 1, I think. So, the reduction rate measures how much the performance is reduced in the second time.

I have two conditions for this dataset: 1. I have a total sample size, overall mean of reduction rate for all patients (one number), and interquartile range; 2. I have a total sample size and individual reduction rate.

My question is how to compute the standard error for these two conditions? I am suddenly confused about the equation. For the first condition, I thought I could compute the standard error simply by using SQRT(p*(1-p)/n), but I am not sure if this is suitable for my scenario. Could anyone help me with it? Thank you so much!

#### fed2

##### Active Member
im not totally sure what your asking butt im prutty sure SQRT(p*(1-p)/n) is not teh formula you seek. what you got sounds like a 'percent change from baseline' and is usally treated as a continous variable, i stdev/sqrt(n) or something, or whatever.