A study investigated the use of social media by freshman. One question asked if the person answering ever stayed up late to chat with friends and ended up sleep deprived. It was thought that at least 80% of all people of freshman age would stay up late. If the study sampled 400 students, what is the mean number of students staying up late in random samples of n = 400 in the freshman population?
A)80
B)160
C)240
D)320

Question

Quizplus · Accepted Answer

The mean number of students staying up late in random samples of n = 400 is found by multiplying the sample size (n = 400) by the proportion expected to stay up late (80% or 0.8). Thus, 400 * 0.8 = 320.

A Study Investigated the Use of Social Media by Freshman