How to find variance

What if my face detector detects faces to within 10 pixels of the actual face location 95% of the time. If we assume this error is Gaussian-distributed,how to get its variance? Total are 4 coordinates

Answer 1

[bym]

unless I misunderstand your question, 95% is 1.96 standard deviations (two sided). You didn't mention if the 10 pixels are ±, so I assume it is the total variation. Then the variance is

(10/(2*1.96))^2

ans =

      6.5077

[Walter Roberson]

I don't see at the moment where the 2* is arising?

[Marium Malik]

Yes,it is the total variation. I didnt get why 1.96 is multiplied by 2?

[Marium Malik]

And how the standard deviation is calculated for 95%?