In: Statistics and Probability
Recall again that Rind & Bordia (1996) investigated whether
or not drawing a happy face
on customers’ checks increased the amount of tips received by a
waitress at an upscale
restaurant on a university campus. During the lunch hour a waitress
drew a happy,
smiling face on the checks of a random half of her customers. The
remaining half of the
customers received a check with no drawing (18 points).
The tip percentages for the control group (no happy face) are as
follows:
45% 39% 36% 34% 34% 33% 31% 31% 30% 30% 28%
28% 28% 27% 27% 25% 23% 22% 21% 21% 20% 18%
8%
The tip percentages for the experimental group (happy face) are as
follows:
72% 65% 47% 44% 41% 40% 34% 33% 33% 30% 29%
28% 27% 27% 25% 24% 24% 23% 22% 21% 21% 17%
This time, you are to perform a “hypothesis test” using the tip
data, answering each of
the questions below. For short-answer questions, be brief. However,
you must give
enough detail to justify your answers. Single-sentence responses
will generally not
suffice, but do not exceed a paragraph for any given answer.
f. Recall that one of the assumptions of the independent t-test
is homogeneity
of variance. If you had to explain this assumption to someone with
little
statistical expertise, how would you explain it?
TOPIC: Homoscedasticity of variance assumption while using the two sample independent t-test.