Chapter 11.2, Problem 63E

a)

To determine

To explain whether the observational study or experimental.

Answer to Problem 63E

This is an experimental study.

Explanation of Solution

First need to understand about the experimental study and observational study:

Experimental study: Assigning people or things to groups and applying some treatment to one group, while the other group does not receive the treatment.

Observation study: In an observational study, measure or survey members of a sample without trying to affect them.

The study having two groups in which they are asking for a rating. Therefore, it is experimental study.

b)

To determine

To explain why chi-square test is not appropriate for this setting.

Answer to Problem 63E

The condition of large counts is not satisfied so, could not use Chi-square test.

Explanation of Solution

Given:

		Rating
		one	Two	Three	Four	Five
Frequency	1 to 5 scale	2	3	1	13	3
	0 to 4 scale	0	0	2	18	8

The expected values are:

		one	Two	Three	Four	Five	Total
1 to 5 scale	Observed	2	3	1	13	3	22
	Expected	0.88	1.32	1.32	13.64	4.84	22.00
0 to 4 scale	Observed	0	0	2	18	8	28
	Expected	1.12	1.68	1.68	17.36	6.16	28.00
Total	Observed	2	3	3	31	11	50
	Expected	2.00	3.00	3.00	31.00	11.00	50.00

The expected values of some categories less than 5. Therefore, the condition of large counts is not satisfied. Hence, could not use Chi-square test.