Can Telling a Joke Affect Whether or Not a Customer

Multiple Choice

Can telling a joke affect whether or not a customer in a coffee bar leaves a tip for the waiter? A study investigated this question at a coffee bar in France. The waiter randomly assigned coffee-ordering customers into three groups: one received a card telling a joke with their bill, another group received a card containing an advertisement for a local restaurant, and the third received no card. The results are shown below.
-Use the Multiple Proportions applet to calculate the follow-up 95% confidence intervals for difference in proportions. Based on the output, which of the following statements are correct? Select all that apply.

A) The probability a customer leaves a tip is statistically significantly larger if a joke card is left than if an ad card is left.
B) The probability a customer leaves a tip is statistically significantly larger if a joke card is left than if no card is left.
C) The probability a customer leaves a tip is not statistically significantly different between the ad card and no card conditions.
D) The probability a customer leaves a tip is not statistically significantly different between the joke card and ad card conditions.