>>Recently one of my students asked me to help with statistics. So, we work with Kaplan AP Statistics. There I see:
>>"...decrease the margin of error by a factor of 1/4...."
>>
>>Just curious, is this passage completely understandable for those of you how was born in English language environment?
>
>Maybe it's my lack of knowledge of statistics but........
>
>At first I thought I knew what was meant but the more I looked at it the less clear it became.

Verbosity killed the book. They didn't have the time to make it simple, like "quadruple the margin of error".