English to Spanish Social Sciences Surveying

I don't know if this refers to a term or has more to do with a metaphor. All suggestions are welcome.

Here we want to exclude from the analysis data that are “more likely to be errors than real values”. So, if the measurements from the members of the population form a normal distribution (bell shaped curve). Then we can estimate what proportion of the observations should be outside a window around the mean of the population.

My attempt: Podemos estimar qué proporción de las observaciones deberían estar fuera de una ventana en torno a la media de la población.

TIA