An educational researcher used school records to determine that, in one school district, 84% of children living in two-parent homes graduated high school while 75% of children living in single-parent homes graduated high school. What type of study is this?

400 patients suffering from chronic back pain were randomly assigned to one of two groups. Over a four-month period, the first group received acupuncture treatments and the second group received a placebo. Patients who received acupuncture treatments improved more than those who received the placebo. What type of study is this?

An observational study is described. Identify the specified element. Among a group of married women who were tracked for ten years, those who worked full time were more likely to divorce than those who did not work full time. Identify the subjects studied.

An observational study is described. Identify the specified element. An examination of the medical records of 10, 000 women who died between 1990 and 2000 showed that those who had taken steroids had a higher risk of osteoperosis. Identify the parameter of interest.

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the drug, and the third group received a placebo. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded. The biggest decrease in blood pressure was for those who received the low dosage of the drug. Identify the response variable measured.

An education researcher was interested in examining the effect of the teaching method and the teacher on students' reading levels. 257 students participated in an experiment. There were two different teachers (Juliana and Felix) and three different teaching methods (A, B, and C). Students were randomly assigned to a teaching method and teacher. At the end of the semester the students took a reading test on which they received a score out of 4. Students who studied with Felix using method B achieved the highest scores. Identify the number of treatments and list them.

Researchers reported that for men, being unmarried increases the risk of depression. These findings were based on the medical records of 400 married men and 500 unmarried men. Since there is no random assignment, this conclusion is not justified because there may be lurking variables. Which of the following are possible lurking variables? I: Rate of depression II: Income III: Type of employment IV: Age V: Gender

Determine whether the experiment is single blind, double blind, or neither Is the Addison Wesley Algebra I text superior to the currently used text, in promoting learning of algebra? Evaluators only are informed that Group A will test from the current text and Group B will test from AW text.

Determine whether the experiment is single blind, double blind, or neither Do Slimquick shakes reduce weight loss? Testers provide Slimquick shakes for participants in groups 1 and 5. Groups 2, 3, and 4 are provided with Stoutslow shakes. Results are evaluated by the group identifier, with no treatment information communicated.

In an experiment, the primary purpose of blinding is to reduce

Which is not a critical part of designing a good experiment?

Does donating blood lower cholesterol levels? Fifty volunteers have a cholesterol test, then donate blood, and then have another cholesterol test. Which aspect of experimental design is present?