Student researchers at Hope College were interested in cell phone usage by students on campus and how it varied during different times of the day. They observed students walking around campus, 232 students during the afternoon and 115 students during evening, and recorded how many were using their phones in some fashion. The results are shown in the table. We will assume these are representative samples of all students at this college. Is the proportion of students on their phones during the afternoon different than in the evening?

a. Identify the observational units and how many there are. 

b. Identify the explanatory and response variables. Also identify the type (categorical or quantitative) of each. 

c. What are the conditional proportions of people that were using their phones in the afternoon and the evening? 

d. Based on the conditional proportions from part (c), does it appear there is an association between the time of day and phone usage for students walking on campus? Explain.

Transcribed Image Text:

Using phone Not using phone Total Afternoon 48 184 232 Evening 45 70 115 Total 93 254 347