A tea manufacturer is trying to decide whether to add peach flavoring or mango flavoring to green tea for a new product. A study is done by stopping customers at a grocery store and asking them to drink a small cup of tea with each flavoring, then to rate each of the two flavors on a scale from 1 to 10 . The order in which the teas are presented is randomly assigned for each person. What type of study is this?
a. An observational study.
b. A sample survey.
c. A case-control study.
d. A matched-pairs design.
Q. 2A difficult birth may put a baby at greater risk for autism, according to a study that may provide clues to the causes of the devastating neurological disability. The Centers for Disease Control and Prevention said that in a study of 698 Danish children who had the developmental disorder (autism), researchers found a disproportionately high number had been born before the 35th week of pregnancy, had suffered from low birth weights and were in a breech position at birth. What type of study is this?
a. Retrospective
b. Prospective
Q. 3A sample of 16,000 women was randomly assigned to take HRT (Hormone Replacement Therapy) or a placebo for 8 years. The results found a larger proportion of heart attacks among women taking HRT than placebo. What type of study is this?
a. Retrospective
b. Prospective
Q. 4A case-control study found higher exposure to gases, dusts, and fumes in the workplace among patients with bronchitis (an inflammation of the lungs) than among patients without bronchitis. What type of study is this?
a. Retrospective
b. Prospective
Q. 5A researcher designed a study to assess whether grades in a statistics course could be improved by using a new teaching technique. The 250 students enrolled in a large introductory statistics class are also enrolled in one of 20 lab sections. The 20 lab sections are randomly divided into 2 groups of 10 lab sections each. The students in the first set of 10 lab sections are taught by this new method. The students in the remaining 10 lab sections are taught using the old techniques. The grades at the end of the term are then compared. Assume that the students do not know if the method they are being taught with is the old or the new method. Suppose the students in the new group were mostly upper-classmen and the students in the old group were mostly first and second-year students. What is the statistical name for the variable year in school in this study?
Q. 6A researcher designed a study to assess whether grades in a statistics course could be improved by using a new teaching technique. The 250 students enrolled in a large introductory statistics class are also enrolled in one of 20 lab sections. The 20 lab sections are randomly divided into 2 groups of 10 lab sections each. The students in the first set of 10 lab sections are taught by this new method. The students in the remaining 10 lab sections are taught using the old techniques. The grades at the end of the term are then compared. Assume that the students do not know if the method they are being taught with is the old or the new method. Identify the explanatory variable and the response variable in this study.
Q. 7A researcher designed a study to assess whether grades in a statistics course could be improved by using a new teaching technique. The 250 students enrolled in a large introductory statistics class are also enrolled in one of 20 lab sections. The 20 lab sections are randomly divided into 2 groups of 10 lab sections each. The students in the first set of 10 lab sections are taught by this new method. The students in the remaining 10 lab sections are taught using the old techniques. The grades at the end of the term are then compared. Assume that the students do not know if the method they are being taught with is the old or the new method. What type of study is described above? Explain your answer.
Q. 8You wish to study the effect of a tutoring program to help improve student grades in an introductory statistics course. Propose a matched-pairs study design to answer the question.
Quick Reply
