Question description

 

1.The EPA claims that fluoride in children's drinking water should be at a mean level of less than 1.2 ppm, or parts per million, to reduce the number of dental cavities. Identify the Type I error.

a	Fail to support the claim σ < 1.2 when σ < 1.2 is true.

b	Support the claim μ < 1.2 when μ = 1.2 is true.

c	Support the claim σ < 1.2 when σ = 1.2 is true.

d	Fail to support the claim μ < 1.2 when μ < 1.2 is true.

2.medical researchers studying two therapies for treating patients infected with Hepatitis C found the following data. Assume a .05 significance level for testing the claim that the proportions are not equal. Also, assume the two simple random samples are independent and that the conditions np ≥ 5 and nq ≥ 5 are satisfied.

Â	Therapy 1	Therapy 2
Number of patients	39	47
Eliminated Hepatitis	20	13
C infection	Â	Â

Construct a 95% confidence interval estimate of the odds ratio of the odds for having Hepatitis C after Therapy 1 to the odds for having Hepatitis C after Therapy 2. Give your answer with two decimals, e.g., (12.34,56.78)

3. biologists, researching the effects of adding limestone sand as buffer for acid rain effects in streams, monitored the pH levels of two streams each month for 36 months. The first stream had a mean pH level of 6.8 with a standard deviation of 2.3. The control stream had a mean pH level of 9.2 with a standard deviation of 1.5. Assume a .05 significance level for testing the claim that the mean pH of the first stream was less (more acidic) than the mean pH of the control stream. Also, assume the two samples are independent simple random samples selected from normally distributed populations, but do not assume that the population standard deviations are equal.

Find the t test statistic. Give your answer with two decimals, e.g., 9.87

 

4. There is a significant linear correlation between the numerical abundance of floating insects in a certain river and the number of insect-eating fish in the river. Identify the choice that contains a conclusion with a common correlation error.

a	Conclusion: an decrease in floating insects causes a decrease in insect-eating fish

b	Conclusion: r results in a value close to -1

c	Conclusion: an increase in floating insects is related to an increase in insect-eating fish

d	Conclusion: r results in a value close to 1

.5. use a .05 significance level and the observed frequencies of 70 Neonatal deaths to test the claim that number of neonatal deaths on each day of the week is equally likely.

Mon	Tues	Wed	Thurs	Fri	Sat	Sun
10	9	5	8	15	12	11

Determine the value of the χ2 test statistic. Give your answer to two decimals, e.g., 12.34 .

6. using a .01 significance level, test the claim that the proportions of people who favor/oppose pro-choice on the abortion issue are the same for the males and females.


Gender

Â	Male	Female
Favor Pro-Choice	65	120
Oppose Pro-Choice	42	38

Do you reject the null hypothesis, at the .01 significance level? Enter Y for yes (reject), N for no (fail to reject).

7. the table represents results from an experiment with patients afflicted with eczema on both arms. Each patient was treated with an immune modulator cream on one arm and a topical steroid cream on the other arm. Using a .05 significance level, apply McNemar's test to test the following claim: The proportion of patients with no cure on the immune modulator treated arm and a cure on the topical steroid treated arm is the same as the proportion of patients with a cure on the immune modulator treated arm and no cure on the topical steroid treated arm.

Â

Â

Immune Modulator Cream

Â	Â	Cure	No Cure
Topical Steroid	Cure	25	11
Cream	No Cure	42	22

Do you reject the null hypothesis, at the .05 significance level? Enter Y for yes (reject), N for no (fail to reject).

 

8 . geneticists studying carriers of genetic diseases followed subjects subdivided by race. Researchers randomly selected seven patients per race who had been identified as carrying a certain gene for a genetic disease; these patients were followed to determine the number of their siblings who also carried the gene for the genetic disease. Use a One-Way ANOVA at a .05 significance level to test the claim that the means from the different races are not all the same.

Caucasian	African-American	Other
2	0	0
3	0	1
3	1	2
3	2	2
4	2	2
5	2	3
5	4	4

Do you reject the null hypothesis, at the .05 significance level? Enter Y for yes (reject), N for no (fail to reject).

9. another way to conduct a Two-Way ANOVA is to conduct two separate One-Way ANOVAs.

True

False

 

 

10. Use the following technology display from a Two-Way ANOVA to answer this question. Biologists studying habitat use in Lepidopteran moths measured the number of savannah moths found at three randomly selected prairie sites with two potential habitat interferences (expansion of row crops and grazing). Use a .05 significance level.

Source	Df	SS	MS	F	P
Site	2	.1905	.0952	.0381	.9627
Habitat	1	304.0238	304.0238	121.6095	.0000
Site*Habitat	2	.1905	.0952	.0381	.9627

What is the value of the F test statistic for the habitat effect?