In "An Informal Look at Use of Bakery Department Tongs and Tissues," a researcher named Trinkaus reported: "Of 108 people observed extracting for purchase rolls or pastries from displayed bulk stock in food supermarket bakery departments, about 90% used their hands for item selection and withdrawal rather than the store provided tongs. In stores where tissues were provided instead of tongs, approximately 60% of the 133 people who were observed used their hands."
a. Was this an experiment or an observational study?
b. Are the relevant proportions (0.90 and 0.60) statistics or parameters?
c. Should the proportions be denoted p1 and p2 or and ?
d. Does the difference between 90% and 60% seem large enough to suggest that, in general, people opt for hands instead of tongs more than they opt for hands instead of tissues?
e. What if the difference (0.90 versus 0.60) had come about from observing just 10 people each in stores with tongs and with tissues; would this be more convincing or less convincing that, in general, people opt for hands instead of tongs more than they opt for hands instead of tissues?