Question

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.

i. Obtain the appropriate test statistic. From the SPSS menus choose Analyze
and Compare Means, followed by the appropriate test.

Answer 1

Ho: There is no significant difference b/w happy faces and not happy faces due to tip percentage.

H1: There is significant difference b/w happy faces and not happy faces due to tip percentage.

level of significance :0.05

Procedure in SPSS

1) Enter the data in two columns named as No_Happy_face and Happy_face resp.

2)go to analyse --> Compare means -->Paired Sample t test

Enter both variable together in paired Variable box.--> OK

Dataset

No_Happy_face	Happy_face
45.00	72.00
39.00	65.00
36.00	47.00
34.00	44.00
34.00	41.00
33.00	40.00
31.00	34.00
31.00	33.00
30.00	33.00
30.00	30.00
28.00	29.00
28.00	28.00
28.00	27.00
27.00	27.00
27.00	25.00
25.00	24.00
23.00	24.00
22.00	23.00
21.00	22.00
20.00	21.00
18.00	21.00
8.00	17.00
22	22

Paired Samples Statistics
		Mean	N	Std. Deviation	Std. Error Mean
Pair 1	No_Happy_face	28.0909	22	7.81274	1.66568
	Happy_face	33.0455	22	13.95393	2.97499

Paired Samples Correlations
		N	Correlation	Sig.
Pair 1	No_Happy_face & Happy_face	22	.888	.000

Paired Samples Test
		Paired Differences					t	df	Sig. (2-tailed)
		Mean	Std. Deviation	Std. Error Mean	95% Confidence Interval of the Difference
					Lower	Upper
Pair 1	No_Happy_face - Happy_face	-4.95455	7.88898	1.68194	-8.45232	-1.45677	-2.946	21	.008

Here p - value is less than 0.05 hence we reject the null hypothesis and conclude that there is significant difference in happy faces and not happy faces due to increase in tip percentage.