After volunteering for an experimental study, nora is included into a group of 30-year olds. she finds that there are other groups having people both younger and older than her. the study's results show that the mental scores of the younger lot are higher than the rest. nora was part of a

I believe the answer is: cross-sectional study

cross-sectional study refers to a type of observational study that use a group of subject from a population with a specific characteristic from a specific point of time. This type of study is usually used to assess the prevalence of acute or chronic conditions and not the perfect type to be used to find a causal relationship between variables,.

explanation:

it was a suprise attack organized by geogre washington against the hessian forces in trenton, new jersey. it began the night o december 25, 1776 and ended december 26, 1776