A study is being planned to assess whether a topical antiallergic eye drop is effective in preventing the signs and symptoms of allergic conjunctivitis. In a pilot study, at an initial visit, participants are given an allergen challenge; that is, they are subjected to a substance that provokes allergy signs (e.g., cat dander) and their redness score is noted 10 minutes after the allergen challenge (visit 1 score). At a follow-up visit, the same procedure is followed, except that participants are given an active eye drop in one eye and the placebo in the fellow eye 3 hours before the challenge; a visit 2 score is obtained 10 minutes after the challenge. The data collected are shown in Table 8.26.
Table 8.26 Effect of an eye drop in reducing ocular redness among participants subjected to an allergen challenge
aThe redness score
Suppose 60 participants are enrolled in the main study. How much power would the study have to detect a 0.5-unit mean difference if a two-sided test is used with a significance level of .05?
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Chapter 8 Solutions
EBK FUNDAMENTALS OF BIOSTATISTICS
- What is an experiment?arrow_forwardA group of disabled women ages 65 and older were followed for several years. It was found that those who had a vitamin B12 deficiency were twice as likely to suffer from severe depressions than those who did not.a. Describe the type of study being performed.b. Describe the explanatory variable(s) and response variable(s).arrow_forwardA study on the effects of color on easing test anxiety compared anxiety test scores of participants who completed a test printed on either soft yellow paper or harsh green paper. The scores for the 10 participants who completed the yellow and the 10 participants who completed it on the green paper are below (Table 5). Using an alpha level of .05, do participants who use the yellow paper report lower test anxiety than those who wrote it on the harsh green paper? Table 5. Anxiety scoresarrow_forward
- Define and explain Type I and Type II errors and relate each to the selection of an alpha level.arrow_forwardThe Dependent variable is the Effectiveness of a new therapeutic technique or Recall on intrusive thougnts? Why?arrow_forwardHave you heard of “pet therapy”? Access to a pet (typically, but not limited to, a dog) has been shown to be associated with beneficial physical responses like lowered blood pressure and reduced anxiety. In a review of the pet therapy literature, Giaquinto and Vlanetini (2009) describe a study that compared two groups of heart patients. Group 1 consisted of patients with high blood pressure and who owned pets. These participants were matched with participants in a control group who also had high blood pressure but did not own pets. Six months later, blood pressure was measured in both groups. Does having a pet reduce blood pressure? what statistical test should be used and why?arrow_forward
- Benzene is a pollutant that, according to studies, can be associated with health problems. Benzene is found in air, water, and soil and comes from both industrial and natural sources. Benzene levels in indoor air are generally higher than outdoors. The main source of benzene in indoor air appears to be tobacco smoke, thus the combustion of tobacco is a major source of pollution. Benzene levels are measured in a random sample of 36 bars in a city, obtaining an average benzene level of 19.2 mg / m3, with a standard deviation of 2.1 mg / m3. Estimate the mean benzene level in bars in this city using a 95% confidence interval. (do your calculations to 4 decimal places) (need the process can be by hand ,Excel or R.) a)Other solution b)[18.48946, 19.91054] c)[19.0950, 19.3050] d)[18.5140, 19.8859] e)[18.6243, 19.7757] f)[18.4315, 19.7936]arrow_forwardA recent study on the effects of Tamiflu looked into whether the antiviral medication can reduce the duration of the flu or not. To test this, researchers selected sample of 42 individuals recently diagnosed with the flu. Twenty-one of these individuals were given a placebo, and their average flu durations was 12.6 days (SD = 1.88). The remaining 21 subjects were given Tamiflu, and their average flu duration was 11.4 days (SD = 1.58). Did Tamiflu make reduce the duration of the flu? What is the effect size for this difference? state the null and alternavive hypthesis, aplha level of 0.05 please text the null hypthesis and draw the rejction regionarrow_forwardThe general population of people with Major Depressive Disorder (MDD) has a known average in regards to symptom severity. These scores are measured on the Brief Depression Inventory, which uses a 0-100 scale, with higher scores indicating greater symptom severity. Researchers at Stanford select a sample of volunteers who meet MDD criteria. That sample of people participate in Cognitive Behavioral Therapy for a period of time, and their symptom severity is measured on the Brief Depression Inventory. The sample's average score is then compared to the general population average for people with MDD. Researchers find that Cognitive Behavioral Therapy appears to treat MDD fairly well! How did researchers most likely analyze their data given this experimental setup? O Single Sample T O Paired Samples T O Independent Samples T O ANOVA O Correlationarrow_forward
- Over a 4-month period, among 30 people with bipolar disorder, patients who were given a high dose (10 g/day) of omega-3 fats from fish oil improved more than those given a placebo. This experiment involved a control group of subjects who received a placebo. Why didn't the experimenters just give everyone the omega-3 fats to see if they improved? Choose the correct answer below. O A. They need to avoid confounding the participants. O B. They need to compare omega-3 results to something. O C. They need to conserve omega-3 fats. O D. They need to blind the participants.arrow_forwardOverproduction of uric acid in the body can be an indication of cell breakdown. This may be an advance indication of illness such as gout, leukemia, or lymphoma. Over a period of months, and adult male patient has taken 13 blood test for uric acid. The main concentration was X=5.41 mg/dl. The distribution of uric acid and healthy adult meals can be assumed to be normal, with o=1.81 mg/dl. find a 95% confidence interval for the population mean concentration of uric acid in the patient's blood. What is the margin of error? (Round your answers to two decimal places.) lower limit= upper limit=arrow_forwardA new drug to treat psoriasis has been developed and is in clinical testing. Assume that those individuals given the drug are examined before receiving the treatment and then again after receiving the treatment to determine if there was a change in their symptom status. If the initial results showed that 2.0% of individuals entered the study in remission, 77.0% of individuals entered the study with mild symptoms, 16.0% of individuals entered the study with moderate symptoms, and 5.0% entered the study with severe symptoms calculate and interpret a chi-squared test to determine if the drug was effective treating psoriasis given the information below from the final examination. Remission (No Symptoms of Psoriasis) Mild Symptoms of Psoriasis Moderate Symptoms of Psoriasis Severe Symptoms of Psoriasis Total Number of Participants to Receive the Drug Number of Participants 380 520 95 5 1000 A) We reject H0 because 310.075 is greater than 5.99. We have…arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillBig Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt
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