Concept explainers
In an experiment to compare two different surgical procedures for hernia repair (“A Single-Blinded, Randomized Comparison of Laparoscopic Versus Open Hernia Repair in Children,” Pediatrics [2009]: 332–336), 89 children were assigned at random to one of the two surgical methods. The methods studied were laparoscopic repair and open repair. In laparoscopic repair, three small incisions are made and the surgeon works through these incisions with the aid of a small camera that is inserted through one of the incisions. In the open repair, a larger incision is used to open the abdomen. One of the response variables in this study was the amount of medication that was given after the surgery for the control of pain and nausea. The paper states “For postoperative pain, rescue fentanyl (1 μg/kg) and for nausea, ondansetron (0.1 mg/kg) were given as judged necessary by the attending nurse blinded to the operative approach.”
- a. Why do you think it was important that the nurse who administered the medications did not know which type of surgery was performed?
- b. Explain why it was not possible for this experiment to be double-blind.
Trending nowThis is a popular solution!
Chapter 2 Solutions
Introduction to Statistics and Data Analysis
Additional Math Textbook Solutions
Basic Business Statistics, Student Value Edition
Elementary Statistics: A Step By Step Approach
Business Statistics: A First Course (7th Edition)
Statistics: The Art and Science of Learning from Data (4th Edition)
Introductory Statistics (2nd Edition)
Statistics for Engineers and Scientists
- What is meant by the sample space of an experiment?arrow_forwardWhat is an experiment?arrow_forwardA large clinical trial of the effect of diet on breast cancer assigned women at random to either a normal diet or a low-fat diet. To check that the random assignment did produce comparable groups, we can compare the two groups at the start of the study. Asked if there is a family history of breast cancer: 1276 of the 5964 women in the low-fat group and 1507 of the 7726 women in the control group said "Yes." If the random assignment worked well, there should not be a significant difference in the proportions with a family history of breast cancer. How significant is the observed difference? State: Is there evidence of a difference in the proportion of women with a family history of breast cancer between the treatment and control groups? Plan: Let pi be the proportion for the treatment group, and Pz the proportion for the control group. State the hypotheses for your test. Ha:Pi + P2 Solve: Give the value of the test statistic. Use the calculator. Select an answer ♥ Ho:pi = p2 What is the…arrow_forward
- In randomized, double-blind clinical trials of a new vaccine, monkeys were randomly divided into two groups. Subjects in group 1 received the new vaccine while subjects in group 2 received a control vaccine. After the second dose, 117 of 750 subjects in the experimental group (group 1) experienced drowsiness as a side effect. After the second dose, 74 of 631 of the subjects in the control group (group 2) experienced drowsiness as a side effect. Does the evidence suggest that a higher proportion of subjects in group 1 experienced drowsiness as a side effect than subjects in group 2 at the a = 0.05 level of significance? Verify the model requirements. Select all that apply. O A. The samples are independent. B. The sample size is more than 5% of the population size for each sample. OC. n,P, (1-P1) 2 10 and n2p2 (1- P2) 2 10 D. The data come from a population that is normally distributed. E. The sample size is less than 5% of the population size for each sample. O F. The samples are…arrow_forwardIn randomized, double-blind clinical trials of a new vaccine, monkeys were randomly divided into two groups. Subjects in group 1 received the new vaccine while subjects in group 2 received a control vaccine. After the second dose, 117 of 750 subjects in the experimental group (group 1) experienced drowsiness as a side effect. After the second dose, 74 of 631 of the subjects in the control group (group 2) experienced drowsiness as a side effect. Does the evidence suggest that a higher proportion of subjects in group 1 experienced drowsiness as a side effect than subjects in group 2 at the a = 0.05 level of significance? Determine the P-value for this hypothesis test. (Round to three decimal places as needed.) Interpret the P-value. If the population proportions are one would expect a sample difference proportion the one observed in about out of 1000 repetitions of this experiment. (Round to the nearest integer as needed.) State the conclusion for this hypothesis test. A. Reject Ho.…arrow_forwardIn randomized, double-blind clinical trials of a new vaccine, rats were randomly divided into two groups. Subjects in group 1 received the new vaccine while subjects in group 2 received a control vaccine. After the second dose, 111 of 670 subjects in the experimental group (group 1) experienced drowsiness as a side effect. After the second dose, 68 of 551 of the subjects in the control group (group 2) experienced drowsiness as a side effect. Does the evidence suggest that a higher proportion of subjects in group 1 experienced drowsiness as a side effect than subjects in group 2 at the α=0.05 level of significance? a. Find the test statistic for this hypothesis test. Round to two decimal places as needed.arrow_forward
- In randomized, double-blind clinical trials of a new vaccine, toddlers were randomly divided into two groups. Subjects in group 1 received the new vaccine while subjects in group 2 received a control vaccine. After the second dose, 121 of 379 subjects in the experimental group (group 1) experienced nausea as a side effect. After the second dose, 150 of 595 of the subjects in the control group (group 2) experienced nausea as a side effect. Does the evidence suggest that a higher proportion of subjects in group 1 experienced nausea as a side effect than subjects in group 2 at the α = 0.10 level of significance?arrow_forwardMigraine and Acupuncture: A migraine is a particularly painful type of headache, which patients sometimes wish to treat with acupuncture. To determine whether acupuncture relieves migraine pain, researchers conducted a randomized controlled study where 161 patients diagnosed with migraine headaches were randomly assigned to one of two groups: treatment or control. 65 patients in the treatment group received acupuncture that is specifically designed to treat migraines. 96 patients in the control group received placebo acupuncture (needle insertion at non-acupoint locations). 24 hours after patients received acupuncture, they were asked if they were pain free. Results are summarized in the contingency table below. Test to see if migraine pain relief is dependent on receiving acupuncture. Use αα = 0.05. Pain Free: Yes Pain Free: No Total Treatment 13 52 65 Control 5 91 96 Total 18 143 161 b) Fill in the expected values, round answers to at least 4 decimal places.…arrow_forwardMigraine and Acupuncture: A migraine is a particularly painful type of headache, which patients sometimes wish to treat with acupuncture. To determine whether acupuncture relieves migraine pain, researchers conducted a randomized controlled study where 151 patients diagnosed with migraine headaches were randomly assigned to one of two groups: treatment or control. 66 patients in the treatment group received acupuncture that is specifically designed to treat migraines. 85 patients in the control group received placebo acupuncture (needle insertion at non-acupoint locations). 24 hours after patients received acupuncture, they were asked if they were pain free. Results are summarized in the contingency table below. Test to see if migraine pain relief is dependent on receiving acupuncture. Use a = 0.05. Pain Free: Pain Free: Total Yes No Treatment 19 47 66 Control 7 78 85 Total 26 125 151 a) What is the correct null hypothesis? Ho: Migraine pain relief is independent on receiving…arrow_forward
- Migraine and Acupuncture: A migraine is a particularly painful type of headache, which patients sometimes wish to treat with acupuncture. To determine whether acupuncture relieves migraine pain, researchers conducted a randomized controlled study where 151 patients diagnosed with migraine headaches were randomly assigned to one of two groups: treatment or control. 66 patients in the treatment group received acupuncture that is specifically designed to treat migraines. 85 patients in the control group received placebo acupuncture (needle insertion at non-acupoint locations). 24 hours after patients received acupuncture, they were asked if they were pain free. Results are summarized in the contingency table below. Test to see if migraine pain relief is dependent on receiving acupuncture. Use a = 0.05. Pain Free: Pain Free: Total Yes No Treatment 19 47 66 Control 7 78 85 Total 26 125 151 a) What is the correct null hypothesis? Họ: Migraine pain relief is independent on receivin…arrow_forwardMigraine and Acupuncture: A migraine is a particularly painful type of headache, which patients sometimes wish to treat with acupuncture. To determine whether acupuncture relieves migraine pain, researchers conducted a randomized controlled study where 164 patients diagnosed with migraine headaches were randomly assigned to one of two groups: treatment or control. 70 patients in the treatment group received acupuncture that is specifically designed to treat migraines. 94 patients in the control group received placebo acupuncture (needle insertion at non-acupoint locations). 24 hours after patients received acupuncture, they were asked if they were pain free. Results are summarized in the contingency table below. Test to see if migraine pain relief is dependent on receiving acupuncture. Use a = 0.05. Pain Free: Yes Pain Free: No Total Treatment Control Total 19 51 70 9 85 94 28 136 164 a) What is the correct null hypothesis? O Ho: P1 P2 P3 = P4 O Ho: Migraine pain relief is dependent on…arrow_forwardMigraine and Acupuncture: A migraine is a particularly painful type of headache, which patients sometimes wish to treat with acupuncture. To determine whether acupuncture relieves migraine pain, researchers conducted a randomized controlled study where 169 patients diagnosed with migraine headaches were randomly assigned to one of two groups: treatment or control. 66 patients in the treatment group received acupuncture that is specifically designed to treat migraines. 103 patients in the control group received placebo acupuncture (needle insertion at non-acupoint locations). 24 hours after patients received acupuncture, they were asked if they were pain free. Results are summarized in the contingency table below. Test to see if migraine pain relief is dependent on receiving acupuncture. Use a = .05. Pain Free: Pain Free: Total Yes No Treatment 16 50 66 Control 9 94 103 Total 25 144 169arrow_forward
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGALCollege Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage Learning