Question

A study of identity theft looked at how well consumers protect themselves from this increasingly prevalent crime. The behaviors of 63 college students were compared with the behaviors of 59 nonstudents. One of the questions was "When asked to create a password, I have used either my mother's maiden name, or my pet's name, or my birth date, or the last four digits of my social security number, or a series of consecutive numbers." For the students, 24 agreed with this statement while 30 of the nonstudents agreed.

(a) Display the data in a two-way table.

	Students		Nonstudents		Total
Agreed
Disagreed
Total					122

Perform the chi-square test. (Round your χ² to three decimal places and round your P-value to four decimal places.)

χ2	=
df	=
P-value	=

Summarize the results.

We can conclude at the 5% level that students and nonstudents differ in the response to this question.

We cannot conclude at the 5% level that students and nonstudents differ in the response to this question.    

(b) Reanalyze the data using the methods for comparing two proportions that we studied in the previous chapter. Compare the results and verify that the chi-square statistic is the square of the z statistic. (Test students who agreed minus nonstudents who agreed. Round your z to two decimal places and round your P-value to four decimal places.)

z	=
P-value	=

(c) The students in this study were junior and senior college students from two sections of a course in Internet marketing at a large northeastern university. The nonstudents were a group of individuals who were recruited to attend commercial focus groups on the West Coast conducted by a lifestyle marketing organization. Discuss how the method of selecting the subjects in this study relates to the conclusions that can be drawn from it.

Answer 1

a)

Students	Students	Nonstudents	Total
Agreed	24	30	54
Disagreed	39	29	68
Total	63	59	122

		Students	Nonstudents	Total
Agreed	Observed	24	30	54
	Expected	27.89	26.11	54.00
	O - E	-3.89	3.89	0.00
	(O - E)² / E	0.54	0.58	1.12
Disagreed	Observed	39	29	68
	Expected	35.11	32.89	68.00
	O - E	3.89	-3.89	0.00
	(O - E)² / E	0.43	0.46	0.89
Total	Observed	63	59	122
	Expected	63.00	59.00	122.00
	O - E	0.00	0.00	0.00
	(O - E)² / E	0.97	1.04	2.01
		2.01	chi-square
		1	df
		.1564	p-value

Perform the chi-square test. (Round your χ² to three decimal places and round your P-value to four decimal places.)

χ2	=2.008
df	=1
P-value	=0.1564

We cannot conclude at the 5% level that students and nonstudents differ in the response to this question.

b)

p1	p2	pc
0.381	0.5085	0.4426	p (as decimal)
24/63	30/59	54/122	p (as fraction)
24.	30.	54.	X
63	59	122	n
	-0.1275	difference
	0.	hypothesized difference
	0.09	std. error
	-1.42	z
	.1564	p-value (two-tailed)

Reanalyze the data using the methods for comparing two proportions that we studied in the previous chapter. Compare the results and verify that the chi-square statistic is the square of the z statistic. (Test students who agreed minus nonstudents who agreed. Round your z to two decimal places and round your P-value to four decimal places.)

z	= -1.42
P-value	=0.1564

c)

The conclusions may vary with choice of subjects. If students choose one subject more than this will effect the P value and will resut in the difference in the conclusions.