Chapter 11.2, Problem 39E

To determine

To explain which treatment seems to be most effective and least effective.

Answer to Problem 39E

Patch plus drug is most effective and Nicotine patch is least effective.

Explanation of Solution

Given:

		Successes	Failures	Total
Nicotine patch	Observed	40	204	244
	Expected	61.75	182.25	244.00
	(O - E)² / E	7.66	2.60	10.26
Drug	Observed	74	170	244
	Expected	61.75	182.25	244.00
	(O - E)² / E	2.43	0.82	3.25
Patch plus drug	Observed	87	158	245
	Expected	62.00	183.00	245.00
	(O - E)² / E	10.08	3.41	13.49
Placebo	Observed	25	135	160
	Expected	40.49	119.51	160.00
	(O - E)² / E	5.93	2.01	7.94
Total	Observed	226	667	893
	Expected	226.00	667.00	893.00
	(O - E)² / E	26.10	8.84	34.94
		34.94	chi-square
		3	df
		1.26E-07	p-value

Calculation:

The least effective treatment is Nicotine patch as expected frequency 61.75 is higher than the observed frequency 40. That is, expected frequency deviates most from the observed frequency. The most effective treatment is Patch plus drug as expected frequency 62 is lower than the observed frequency 87.