A Developmental Psychologist Conducts an Experiment to Determine If Exposure

A developmental psychologist conducts an experiment to determine if exposure to an enriched environment shortly after birth will cause increased brain development. Twenty, two month old rats are randomly selected from a pool of one thousand, two month old, rat pups. Ten of the twenty pups are exposed to an enriched environment for three weeks and the other ten to the usual environment for the same period of time. At a suitable time after the exposure, the psychologist measures the number of neurons per cm³ in the brain of each rat. A comparison is then made of the mean number of neurons per cm³ for each group. Identify the following: