stats hw due soon please help

Posted on 2014-11-10 04:14:00 in Statistics by MURPHY

1. A random sample of birth weights of 186 babies has a mean of 3103g and a standard deviation of 696 g (based on data from Cognitive Outcomes of Preschool Children with Prenatal Cocaine Exposure, by Singer et al., Journal of the American Medical Association, Vol. 291, No. 20). These babies were born to mothers who did not use cocaine during their pregnancies.
Construct a 95% CI for the population mean birth weight for all such babies.

2. Experts in the diet industry hypothesize that the true mean weight loss for those that use the Atkins diet is less than or equal to 1.7 pounds. In a test of the Atkins weight loss program, 40 individuals participated in a randomized trial with overweight adults. After 12 months, the mean weight loss was found to be 2.1 pounds with a standard deviation of 4.8 pounds.
a. Construct a 99% CI for the population mean weight loss.
b. Do your results agree or disagree with the industry hypothesis? Why?

3. In a study designed to test the effectiveness of Echinacea for treating upper repiratory tract infections in children, 337 children were treated with Echinacea and 370 other children were given a placebo. The number of days of peak severity of symptoms for the Echinacea treatment group had a mean of 6 days and a standard deviation of 2.3 days. The numbers of days of peak severity of symptoms for the placebo group had a mean of 6.1 days and a standard deviation of 2.4 days (based on data from Efficacy and Safety of Echinacea in Treating Upper Respiratory Tract Infections in Children, by Taylor et al., Journal of the American Medical Associations, Vol. 290, No. 21).
a. Construct a 95% CI for the true mean number of days of peak severity of symptoms for those who receive Echinacea treatment.
b. Construct a 95% CI for the true mean number of days of peak severity of symptoms for those who are given a placebo.
c. Compare the two results. What do the results imply?

4. Listed below are the top 10 salaries (in millions of dollars) of television personalities in a recent year. TV industry executives hypothesize that the true mean salary is equal to 31 million.
38 36 35 27 15 13 12 10 9.6 8.4
a. Construct a 95% CI for the true mean salary.
b. Do your results agree or disagree with the industry hypothesis? Why?

5. Movie industry executives hypothesize, based on a long-history of data and research, that the mean length of movies is 141 minutes. Attached in a data set called movies are 12 randomly selected movie lengths (in minutes).
a. Construct a a 99% CI for the true mean length of movies.
b. Do your results agree or disagree with the industry hypothesis? Why?

6. Attached in a data set called presidents are the ages of presidents at the time of their inaugurations. Construct a 93% CI for the true mean age of presidents.

7. Use the attached data set called earthquake to construct a 84.3% CI for the true mean magnitude of earthquakes (measured on a Richter scale).

8. The US Navy believes that the mean age of test pilots is about 30 years old.
a. Use the attached data set called fighterjet to construct a 96% CI for the true mean age of pilots.
b. Do your results agree or disagree with the established belief? Why?
c. While we are using this data, suppose I had the following question: What is the relationship, if any at all, exists between the age of the test pilot and their pulse rate

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