MA 203DL Excel Project 6

Testing Claims, Part 1 Taken from the exercises for 9.1 and 9.2 in "Elementary Statistics Using Excel, 6^th Edition", Mario Triola

Smoking Cessation Programs

Among 198 smokers who underwent a "sustained care" program, 51 were no longer smoking after six months.Among 199 smokers who underwent a "standard care" program, 30 were no longer smoking after six months. {"Sustained Care Intervention and Post-discharge Smoking Cessation..." Rigotti et al, JAMA Vol 312, no7} We want to use a 0.01 significance level to test the claim that the rate of success for smoking cessation is greater with the sustained care program. 1) Test the claim using a hypothesis test

2) Test the claim by constructing a Confidence Interval

3) Do you conclude that the difference between the two programs has practical significance? Why or why not?

Cardiac Arrest at Day and Night A study investigated survival rates for in-hospital patients who suffered cardiac arrest. Among 58,593 patients who had an arrest during the day, 11,604 survived and were discharged. Among the 28,155 who suffered an arrest at night, 4139 survived and were discharged.("Survival from In-Hospital Cardiac Arrests During Nights and Weekends", JAMA Vol 299, No7; Peberdy et all)

We want to use a 0.01 significance level to test the claim that survival rates are the same for day and night.

4) Test the claim using a hypothesis test

5) Test the claim by constructing a Confidence Interval

6) Does it appear that the survival rates are the same for patients who suffer cardiac arrest during the day and at night?

IQ and Lead Exposure

Data Set 7 "IQ and Lead" lists full scores for a random sample of subjects with low lead levels in their blood and another for those with high levels. Low: n = 78, mean = 92.88462, standard deviation = 15.34451 High: n = 21, mean = 86.90476, standard deviation = 8.988352

7) Use a 0.05 significance level to test the claim that the mean IQ score of people with low blood levels is higher than that of those with high levels.

8) Construct a confidence interval to test your findings.

9) What do you conclude?

Seat Belts A pediatric study done for the American Journal of Public Health looked at seat belt use for children hospitalized after car crashes. For the group of 123 children who had been buckled in, their mean number of days in the ICU was 0.83 with a standard deviation of 1.77. Of the 290 who had not been wearing seat belts, their meantime was 1.39 days in the ICU with a standard deviation of 3.06 days.

10)Use a 0.05 significance level to test the claim that children who wore seat belts had a shorter time in the ICU than those who did not.

11) Construct a confidence interval to test your findings.

12) What do you conclude?

BONUS

Echinacea as a Cold Treatment

In the test 40 of the 45 subjects who took Echinacea developed colds, while 88 of the 103 in the placebo group did. At a 0.05 significance, does it appear that subjects taking Echinacea are less likely to develop a cold? HINT: Test for the cases to be equal, rather than for p1

Independent - finding means and standard deviations
			Remember to adjust the data field as needed for the means and standard devs!
x1 values	x2 values		x1 mean	4.02		Don't forget about degrees of freedom!
4.4	4		x2 mean	4.1		Take the smaller if n1 doesn't equal n2
3.4	3.6					Table t value	2.262
4.8	4.1		s1	0.720802
2.9	4.1		s2	0.352767		E =	0.574031
4.4	3.5								#17 New Text
4.9	4.6		n1	10		Lower Interval Bound	pg471
3.5	4		n2	10			-0.65403
3.7	4.3					Upper Interval Bound
3.4	4.5		t =	-0.31524			0.494031
4.8	4.3		Assuming that Mu1 - Mu2 = 0
			Independent Given Summary Statistics		SIGMA UNKNOWN
			Mean 1	3.39		t =	-2.97895		Round to thousandths
			Mean 2	3.97		Assuming that Mu1 - Mu2 = 0
			S1	0.97
			S2	0.63		Table t value	2.441
			n1	35
			n2	36		E=	0.475261
				Lower Interval Bound	-1.05526
				Upper Interval Bound	-0.10474		Round to hundredths

Dependent
x1	X2	d					n	5
189	170	19		x bar 1	180.8
173	185	-12		x bar 2	177.6		t table value	2.132
183	175	8		d bar	3.2
180	180	0
179	178	1		Remember to update the parameters for the formulas!
				s-sub-d	11.38859
				t =	0.628297
				(assuming mu sub d is 0)
				E =	10.85856
				Lower Interval Bound
					-7.65856
				Upper Interval Bound
					14.05856