Question

1. an experienced server at a restaurant wondered if suggesting a specific dessert to customers would increase the average total bill (and therefore tips). for every table in one shift, the server tossed a coin before approaching the table. if it landed heads, no suggestion for dessert was made. if it landed tails, the server made a specific suggestion for dessert. the server found that tables who were given the dessert suggestion had a higher average total bill, and the difference was statistically significant.

a. what is meant by \statistically significant\?
b. was a random sample used to collect the data?
c. was random assignment used to set up an experiment?
d. what conclusion can be made from the study?

Explanation:

a. "Statistically significant" means that the observed difference in average total bill (between tables with and without dessert suggestion) is unlikely to have occurred by chance.
b. No, a random sample was not used. The data was collected from tables in one shift, which is not a random sample of all possible restaurant tables.
c. Yes, random assignment was used. The server tossed a coin to randomly assign whether to make a dessert suggestion or not.
d. The conclusion is that suggesting a specific dessert to customers is associated with a higher average total bill. However, we cannot be certain of a causal relationship (there could be other factors), but the random assignment helps strengthen the case for a possible causal link.

Answer:

a. The observed difference is unlikely due to chance.
b. No.
c. Yes.
d. Suggesting a dessert is associated with a higher average bill (possible causal link due to random assignment).