Wait staff at restaurants have employed various strategies to increase tips. An article in the Sept. 5, 2005, New Yorker reported that “In one study a waitress received 50% more in tips when she introduced herself by name than when she didn’t.” Consider the following (fictitious) data on tip amount as a percentage of the bill:

Introduction:

No introduction:

Does this data suggest that an introduction increases tips on average by more than 50%? State and test the relevant hypotheses. [Hint: Consider the parameter .]