Exam 6: Gathering Useful Data for Examining Relationships

Use the following information for questions: A 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?

Use the following information for questions: For each relationship, decide whether the variable is an interacting variable or a confounding variable. -A professor found an association between the number of times a student came to office hours and the grade received in the course. The total number of hours that a student studied in the course is

Use the following information for questions: A researcher asked random samples of 50 kindergarten teachers and 50 12th grade teachers how much of their own money they spent on school supplies in the previous school year. They wanted to see if teachers at one grade level spend more than teachers at the other grade level. -In this study, the reply to the question about amount spent on school supplies is an example of

Use the following information for questions: Fifty university students are randomly chosen from the college campus. Their physical fitness routines and academic performance will be assessed. They are asked to maintain a diary over a semester to record their physical activity (i.e. work-outs) every week. At the end of this semester their GPA is recorded as well. The resulting information is categorized per student into two variables: physical activity (recorded as "above average", "average", or "below average") and that semester's GPA. The primary interest of the research project is to understand if physical activity promotes better academic performance. -Which variable is the explanatory variable in this study?

Use the following information for questions: Very young children who live in homes where the television is on most of the time may have more trouble learning how to read than other kids their age, according to a study of media habits of children up to 6 years old. The report, based on a survey of parents, also found that kids in the 6 months to 6-year-old age group spend about two hours a day watching television, playing a video game or using a computer. That's roughly the same amount of time they spend playing outdoors and three times as long as they spend reading or being read to. -What type of study is this?

The purpose of having a control group in a study is

A 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?

Use the following information for questions: A researcher is studying the relationship between sugar consumption and weight gain. Twelve volunteers were randomly assigned to one of two groups. The first group had five participants which were put on a diet low in sugar and the other group with the remaining seven participants received 10% of their calories from sugar. After 8 weeks, weight gain was recorded from each participant. -Which of the following principles was not used in this study?

Use the following information for questions: For each relationship (conclusions from one or more studies), define what the response and explanatory variables are. -The oldest child in a family is more likely to favor the death penalty than the middle or youngest child.

Use the following information for questions: A difficult birth or a history of mental illness in a parent may put a baby at greater risk for autism. The Centers for Disease Control and Prevention said that in a study of 698 Danish children with the developmental disorder, 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. The children, all of whom were born after 1972 and diagnosed with autism before 2000, also were more likely to have a parent who had been diagnosed with schizophrenia-like psychosis before the autism was discovered. -What is the response variable in this study?