Chapter 13 Review Name Date Period Write complete answers, using complete sentences where necessary. Show your work when possible. SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Determine whether the report describes a prospective observational study, a retrospective observational study, or an experiment. 1) In a group of 500 men and women, those who smoked did worse on tests of reaction time 1) than those who did not smoke. 2) 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. 2) 3) An examination of the medical records of 10, 000 women showed that those who were short and fair skinned had a higher risk of osteoperosis. 3) An observational study is described. Identify the specified element. 4) An educational researcher used school records to determine that in the year 2000 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. Determine the parameter of interest. 4) 5) In a group of 500 women, those who smoked moderately did worse on tests of reaction time than those who did not smoke. Identify the subjects studied. 5) 6) Among a group of Canadian men who were tracked for ten years, those who had scored over 130 on intelligence tests were more likely to suffer severe depression than those who had scored below 130 on intelligence tests. Identify the subjects studied. 6) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 7) At St. Luke's hospital in 1998, 674 women were diagnosed with breast cancer. Five years later, 88% of the Caucasian women and 83% of the African American women were still alive. Determine the nature and scope of the conclusion the study can reach. A) For Caucasian and African American women with breast cancer, attending St. Luke's hospital causes an increased chance of surviving five years. B) Since there is no random assignment, there is no way to know that being Caucasian causes women with breast cancer an increased chance of surviving five years; there may have been confounding variables. C) For women with breast cancer, being Caucasian causes an increased chance of surviving five years. D) Since the study is limited to Caucasian and African American women, no conclusion can be reached. E) Since there is no random assignment, there is no way to know that being Caucasian causes women with breast cancer an increased chance of surviving five years; there may have been lurking variables. 7) 1
A designed experiment is described. Identify the specified element. 8) An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test. In a study, there are four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods (A, B, and C). The number of students participating in the study is 258. Students are randomly assigned to a teaching method and teacher. Those who studied wth Sonia using method B achieved the highest scores. Identify the response variable measured. A) The education researcher B) Teaching method C) Teacher D) Method A, method B, method C E) Score on reading test 9) 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. Identify the levels of the factor. A) High blood pressure, low blood pressure B) The one-month period C) Diastolic blood pressure at the start, diastolic blood pressure at the end D) Placebo, low dosage, high dosage E) The experimental drug 10) An education researcher was interested in examining the effect of the teaching method and the teacher on the reading level of students with learning disabilities. 257 students with learning disabilities participated in an experiment. There are four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods (A, B, and C). Students are randomly assigned to a teaching method and a teacher. Those who studied with Sonia using method B achieved the highest scores on a reading test. Identify the subjects studied. A) Teacher B) Students who studied with Sonia using method B C) Students with learning disabilities D) Score on reading test E) Teaching method 11) 780 participants suffering from depression were randomly assigned to one of three groups. Over a four-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. At the end of the period each participant rated their mood on a scale of 1-10. Identify the factor(s) in the experiment and the number of levels for each. A) The experimental drug (3 levels) B) The experimental drug (3 levels), mood (10 levels) C) Mood (10 levels) D) Placebo, low dosage, high dosage (3 levels) E) The dosage of the drug (3 levels) 8) 9) 10) 11) 2
12) A researcher wants to examine the effect of fertilizer and the effect of sunlight on the yield of tomatoes. She bought 60 tomato plants at a local garden store. She randomly assigned 30 tomato plants to be planted on the sunny side of the hill and 30 to be planted on the shady side. The 30 plants which are planted on the shady side are randomly assigned to one of three groups. The first group are grown with no fertilizer, the second group with a small amount of fertilizer, and the third group with a large amount of fertilizer. The 30 plants which are planted on the sunny side are likewise randomly assigned to one of three groups. The first group are grown with no fertilizer, the second group with a small amount of fertilizer and the third group with a large amount of fertilizer. All tomato plants are planted at the same time and are all treated alike (in terms of how much they are watered, weeded etc). Each plant is grown to maturity. The total weight of tomatoes obtained from each plant is recorded. Identify the factor(s) and the number of levels for each. A) Sunny, shady (2 levels) B) Fertilizer (3 levels), blocking variable - location (2 levels) C) No fertilizer, small amount of fertilizer, large amount of fertilizer (3 levels) D) No fertilizer and sunny, small amount of fertilizer and sunny, large amount of fertilizer and sunny, no fertilizer and shady, small amount of fertilizer and shady, large amount of fertilizer and shady (6 levels) E) Fertilizer (3 levels), location (2 levels) 12) Describe the design of the experiment (completely randomized or blocked). 13) 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. A) Completely randomized over one factor (experimental drug), blocked by diastolic blood pressure B) Completely randomized over one factor (diastolic blood pressure), blocked by experimental drug C) Completely randomized over two factors (experimental drug, diastolic blood pressure) D) Completely randomized over one factor (experimental drug) E) Blocked by experimental drug, blocked by diastolic blood pressure 14) A researcher wants to examine the effect of fertilizer and the effect of sunlight on the yield of tomatoes. She bought 60 tomato plants at a local garden store. She randomly assigned 30 tomato plants to be planted on the sunny side of the hill and 30 to be planted on the shady side. The 30 plants which are planted on the shady side are randomly assigned to one of three groups. The first group are grown with no fertilizer, the second group with a small amount of fertilizer, and the third group with a large amount of fertilizer. The 30 plants which are planted on the sunny side are likewise randomly assigned to one of three groups. The first group are grown with no fertilizer, the second group with a small amount of fertilizer, and the third group with a large amount of fertilizer. All tomato plants are planted at the same time and are all treated alike (in terms of how much they are watered, weeded etc). Each plant is grown to maturity. The total weight of tomatoes obtained from each plant is recorded. A) Completely randomized over one factor (fertilizer), blocked by location B) Blocked by fertilizer, blocked by location C) Completely randomized over two factors (fertilizer and location) D) Completely randomized over one factor (location), blocked by fertilizer E) Completely randomized over one factor (fertilizer) 13) 14) 3
Determine whether the experiment is single-blind, double-blind, or neither. 15) A researcher wants to examine the effect of fertilizer and the effect of sunlight on the yield of tomatoes. She bought 60 tomato plants at a local garden store. She randomly assigned 30 tomato plants to be planted on the sunny side of the hill and 30 to be planted on the shady side. Within each group of 30 plants, she randomly assigned plants to one of three groups. The first group is grown with no fertilizer, the second group with a small amount of fertilizer, and the third group with a large amount of fertilizer. All tomato plants are planted at the same time and each plant is grown to maturity. The total weight of tomatoes obtained from each plant is recorded. The person evaluating the results does not know which tomatoes received fertilizer or which were grown on the sunny side. A) Single-blind B) Double-blind C) Neither 16) 780 men suffering from high blood pressure were randomly assigned to one of two groups. Over a four-month period, the first group received an experimental drug and the second group received a placebo. A larger decrease in diastolic blood pressure was observed for those who received the drug. The patients did not know whether they were receiving the drug or the placebo. Neither the technicians administering the treatments nor the physicians evaluating the results knew which participants had received the drug and which the placebo. A) Single-blind B) Double-blind C) Neither 15) 16) Answer the question. 17) A new type of pain reliever is administered to 30 consenting post-operative patients in various hospitals. Although the pain reliever has already been tested for safety and effectiveness, this experiment is to observe and categorize any side-effects. Because of maturity and body mass, it is decided to test the adults separately from the children. 17) The grouping of the adults separate from the children is an example of what? A) Matching B) Controlling C) Reduction of confounding factors D) Stratifying E) Blocking 4
18) A double-blind experiment of an allergy medication is being tested on 100 participants according to this diagram: 18) If Group 2 receives a full dose of the medication, what should Group 1's treatment consist of? A) A placebo B) Stratified doses C) Blocked doses D) A 50% dose E) Randomized doses 19) A pharmaceutical company will be testing a new "one-dosage fits all" medication for treating depression. The pharmaceutical company has 100 willing test subjects that will undergo a 30-day, double-blind experiment. The experiment uses the following diagram as a guide for administering the medication at various doses, from 5% to 125%. 19) What is the most obvious factor missing from this proposed experiment? A) A 100% dosage B) Stratifying must be used. C) Blocking must be used. D) A control group E) Nothing is missing. Basic variations have been accounted for. 5
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Design an appropriate experiment or study. 20) An employer suspects that on Mondays the percentage of employees absent from work is higher than on other days. Design a way he could find out whether there is any merit to his belief. Should he use an experiment or an observational study? He would like to have the information as soon as possible. 20) 21) A researcher has developed a set of breathing exercises and would like to investigate whether they can help to reduce anxiety. She wonders whether the breathing exercises for 15 minutes or for 30 minutes would be more effective. Design an appropriate experiment. 21) Identify the flaw(s) in the experiment or study described. 22) 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. Why is this conclusion not justified? 22) 23) A manufacturer of tennis rackets would like to test their new racket. The company sponsors 10 tennis players who will be playing at Wimbledon. To test the racket, they have each player serve 30 times with their old racket. Then they have each player serve 30 times with the new racket. They compare the percentage of good serves with the two rackets. Identify the flaw(s) in this experiment and suggest some improvements. 23) 6
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 24) At St. Luke's hospital in 1998, 674 women were diagnosed with breast cancer. Five years later, 88% of the Caucasian women and 83% of the African American women were still alive. A researcher concludes that being Caucasian causes women with breast cancer an increased chance of surviving five years. Since there is no random assignment and there may have been lurking variables, this conclusion is not justified. Which of the following are possible lurking variables? 24) I: Income II: Neighborhood where patient lives III: Quality of health care IV: Diet V: Number of years surviving since diagnosis A) I, II, III, IV B) I, III, IV C) I, IV D) I, II, III, IV, V E) II, IV 25) An educational researcher has designed two different methods for teaching a statistics course and would like to investigate which is more effective. He designs an experiment as follows. He will obtain a group of volunteer statistics students. Volunteers will be randomly assigned to one of two groups. Group 1 will be taught the statistics course by Anna Clark using method A and group 2 will be taught by Bob Beauman using method B. At the end of the semester, students will all take the same test. Then the scores for the two groups will be compared. The person grading the tests will be blinded to which group students were in. Identify the most serious flaw in this experiment. A) Since there is no random assignment, there could be lurking variables. B) There is a confounding variable - namely the teacher. C) The person grading the tests may have been biased. D) There is no blocking. E) Volunteers should have been selected randomly. 25) SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Provide an appropriate response. 26) Explain the difference between an observational study and an experiment. 26) 27) In an experiment, explain the difference between the treatments and the factors. 27) 28) A researcher has developed a set of breathing exercises and would like to investigate whether they can help to reduce anxiety. She designs an experiment as follows. She will obtain a group of volunteers suffering from anxiety. They will be given a test to measure the level of their anxiety. Volunteers will be randomly assigned to one of three groups. Those in group 1 will do breathing exercises for 15 minutes per day, those in group 2 will do breathing exercises for 30 minutes per day, and those in group 3 (control group) will do no breathing exercises. After a suitable time period, each person will again take the anxiety test. The researcher will compare the average change in score for the three groups. Is it possible to double-blind this experiment? Explain. 28) 7
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 29) Placebos are a tool for... 29) A) blocking B) randomization C) sampling D) blinding E) control 30) Which of the following is not required in an experimental design? 30) A) blocking B) replication C) control D) randomization E) All are required in an experimental design. 31) Can watching a movie temporarily raise your pulse rate? Researchers have 50 volunteers check their pulse rates. Then they watch an action film, after which they take check their pulse rates once more. Which aspect of experimentation is present in this research? A) blinding B) a control group C) randomization D) a placebo E) none of these 31) 8