quiz week 6, statistics homework help

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.

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.

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.

.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.

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

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.

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.

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.

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.

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