statistic quiz

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. (Points : 1) Fail to support the claim σ < 1.2 when σ < 1.2 is true. Support the claim μ < 1.2 when μ = 1.2 is true. Support the claim σ < 1.2 when σ = 1.2 is true. Fail to support the claim μ < 1.2 when μ < 1.2 is true.

2.) The Common Murre population of birds became endangered in California due to an oil spill. Biologists want to know if their efforts to restore the colony have been successful. Since the breeding colony of birds is site dependent, the mean number of breeding pairs of Common Murres were observed at a specific rock known to be a breeding site. Test the claim that the mean number of breeding pairs of the Common Murre is greater than 400. Assume that a simple random sample has been taken, the population standard deviation is not known, and the population is normally distributed. Use the following raw data collected from seven days of observations: 404 398 402 406 399 405 403 What is the P-value associated with your test statistic? Report your answer with three decimals, e.g., .987 . (Points : 1)

3.) Researchers studying sleep loss followed the length of sleep, in hours, of 10 individuals with insomnia before and after cognitive behavioral therapy (CBT). Assume a .05 significance level to test the claim that there is a difference between the length of sleep of individuals before and after CBT. Also, assume the data consist of matched pairs, the samples are simple random samples, and the pairs of values are from a population having a distribution that is approximately normal.

Individual	1	2	3	4	5	6	7	8	9	10
Before	6	5	4	5	3	4	5	3	4	2
CBT
After	8	8	7	6	7	6	6	5	7	5
CBT

Construct a 95% confidence interval estimate of the mean difference between the lengths of sleep. Give your answer with two decimals, e.g., (12.34,56.78) (Points : 0.5)

4. ) Given: There is a linear correlation coefficient very close to 0 between black willow tree cuttings monitored for survival at 7 days and black willow tree cuttings monitored for survival at 14 days. Identify the choice below that contains a conclusion with a common correlation error. (Points : 1)

Conclusion: there is not a linear relationship between the survival of black willow tree cuttings at 7 days and the survival of black willow tree cuttings at 14 days Conclusion: the survival of black willow tree cuttings at 7 days is not related in any way to the survival of black willow tree cuttings at 14 days Conclusion: an increase in the survival of black willow tree cuttings at 7 days is not linearly related to the survival of black willow tree cuttings at 14 days Conclusion: a decrease in the survival of black willow tree cuttings at 7 days is not linearly related to a decrease in the survival of black willow tree cuttings at 14 days

5.)Use a .05 significance level and the observed frequencies of 144 drownings at the beaches of a randomly selected coastal state to test the claim that the number of drownings for each month is equally likely. Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec 1 3 2 7 14 20 37 33 16 6 2 3 Do you reject the null hypothesis, at the .05 significance level? Enter Y for yes (reject), N for no (fail to reject). (Points : 0.5)

6.) Using a .01 significance level, test the claim that the proportions of fear/do not fear responses are the same for male and female dental patients. Gender

	Male	Female
Fear Dentistry	48	70
Do Not Fear Dentistry	21	32

Do you reject the null hypothesis, at the .01 significance level? Enter Y for yes (reject), N for no (fail to reject). (Points : 0.5)

7.) The table represents results from an experiment with patients afflicted in both eyes with glaucoma. Each patient was treated in one eye with laser surgery and in the other eye was treated with eye drops. Using a .05 significance level, apply McNemar's test to test the following claim: The proportion of patients with no improvement on the laser treated eye and an improvement on the drops treated eye is the same as the proportion of patients with an improvement on the laser treated eye and no improvement on the drops treated eye.

Eye Drop Treatment

		Improvement	No Improvement
Laser Surgery	Improvement	15	10
Treatment	No Improvement	50	25

Do you reject the null hypothesis, at the .05 significance level? Enter Y for yes (reject), N for no (fail to reject). (Points : 0.5)

8.) For a study on Type 1 diabetes, medical graduate students subdivided the United States into four study regions (Northeast, Southeast, Southwest, and Northwest). The students randomly selected seven patients per region and recorded the number of times during a randomly selected month that each patient used insulin shots to regulate blood sugar levels. Use One-Way ANOVA at a .05 significance level to test the claim that the means from the different regions are not the same.

Mean number of times patients used insulin shots to regulate blood sugar levels

Northeast	Southeast	Southwest	Northwest
4	6	4	4
3	5	5	4
3	6	6	5
4	8	6	6
3	6	7	3
2	6	5	5
5	8	4	3

Determine the value of the F test statistic. Give your answer to two decimals, e.g., 12.34 . (Points : 0.5)

9.)

Another way to conduct a Two-Way ANOVA is to conduct two separate One-Way ANOVAs. (Points : 1) 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 site effect? (Points : 0.5)