MATH 3080: Statistical Report Assignment No.9
1.A study tried to examine if the amount of food influences (normal or excessive) the risk of feline lower urinary tract diseases in cats.
The data set is available at Go under the title “Textbook Data Sets” → “Urinary tract disease I.” (Data file:
Study Questions:
(a)Estimate a confidence interval for the difference in proportion of cats with excessive amounts of food between the disease and the non-disease group. Construct a hypothesis test. What is your conclusion?
(b) Make a chi-square test for independence. What is your conclusion?
2.A standard drug was administered to patients suffering from high blood pressure, and responses to therapy can be classified into one of four response categories:
C1: Marked decrease in blood pressure (50%);
C2: Moderate decrease in blood pressure (25%);
C3: Slight decrease in blood pressure (10%);
C4: Stationary or slight increase in blood pressure (15%).
A lab conducted a clinical trial with a random sample of 200 patients.
The data set is available at Go under the title “Textbook Data Sets” → “Blood pressure drug.” (Data file:
Study Questions:
(a)State hypotheses and construct a test to show that the percentages of patients to different categories in the clinical trial are similar to those in the standard drug.
(b)Quantify any results and write the conclusion in words.
3. In a questionnaire 174 people were asked the question: “How important is it to be in a nuclear family?” The researchers are interested in whether there is independence between gender and the opinion on this particular question.
The data set is available at Go under the title “Textbook Data Sets” → “Nuclear family matters.” (Data file:
Study Questions:
(a)Make a chi-square test for independence. What is your conclusion?
(b)Collapse the groups “Little” and “Not.” Make a chi-square test for independence. What is your conclusion?
(c)Does it make sense to collapse the groups “Little” and “Not”? Why or why not?