8. Two randomized, double-blind studies (Study X and Study Y) are conducted to assess the efficacy of a new chemotherapeutic agent.For each study, patients are randomized to receive either placebo or the new experimental chemotherapy, all subjects are thenfollowed for a mean of 5 years. Follow-up rates are 92% in Study X and 91% in Study Y. Results show84Study XStudy YETITILower socioeconomicAverage age (years)Caucasian (%)Experiment53Control Experiment52508489Current smoker (%)151414Control52861325283027Local cancer (%)Heart disease (%)Diabetes (%)7577721012107410157109status (%)The relative risk of dying of cancer is 0.7 in Study X (95% confidence interval of 0.2 to 2.4) and 0.6 in Study Y (95% confidence intervalof 0.5 to 0.7). Which of the following best accounts for this difference in confidence intervals?A) BiasB) Difference in follow-up ratesC) Difference in number of patientsD) Different populationE) Randomization error

The question is asking us to identify the most likely reason for the difference in the confidence…

Answered: 8. Two randomized, double-blind studies…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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Until 2002, hormone replacement therapy (HRT), estrogen and/or progesterone, was commonly prescribed to post-menopausal women. This changed in 2002, when the results of a large clinical trial were published 7500 women were randomized to take HRT, 7100 were randomized to placebo. 170 HRT and 130 placebo women developed invasive breast cancer. Does HRT increase risk of breast cancer? Conduct hypothesis test. Hint: Use randomization distribution to answer the question.
When neither the subject nor those having contact with the subject know the treatment assignment, the study is called unbiased. double-blind. blind. statistically significant. randomized.
Classify the cases/scenario as regards to the appropriate design/analysis for the experiments: A woman learned from a friend that rubbing the leaves with either egg white or coconut oil could enhance the appearance of indoor plants. But she was doubtful that this will induce withering of the leaves. She then plans to conduct an experiment to compare the effects of these two. For better comparison, she would like to include a control (no egg whole nor coconut oil) and the outcome data follows a non-normal distribution. * (Parametric/Nonparametric – Design/Analysis e.g. Par-ANOVA(RCBD), Nonpar-Wilcoxon test) Your answer
The Paleo diet allows only for foods that humans typically consumed over the last 2.5 million years, excluding those agriculture-type foods that arose during the last 10,000 years or so. Researchers randomly divided 500 volunteers into two equal-sized groups. One group spent 6 months on the Paleo diet. The other group received a pamphlet about controlling portion sizes. A randomized treatment assignment was performed, and at the beginning of the study, the average difference in weights between the two groups was about 0 pounds. After the study, the Paleo group had lost an average of 7.1 pounds with a standard deviation of 22.75 pounds while the control group had lost an average of 4.5 pounds with a standard deviation of 11.5 pounds. After failing to reject the null hypothesis support your answer with a p-value (a) P-value = _______
In a randomized block experiment with treatment Factor T , what is the purpose of doing a multiple comparison if the treatment factor effect is significant?
In 2019 Chicago Hope Hospital hired new nurses from two top universities in the country. After one year, the hospital conducts a simple study to analyse whether there is a significant difference in regard to the performance of the nurses who graduated from the two universities. Considering the maximum performance score of 100, the following is the result of independent sampling of the nurses’ performance scores. Assume the scores are not normally distributed. Table attached Question: What statistical method can be applied for this study? Explain your answer
What is the sample size (n=) and what consequences will the sample size have on my analysis and reporting of results?
Acne is a common skin disease that affects most adolescents and can continue into adulthood. A study compared the effectiveness of three acne treatments and a placebo, all in gel form, applied twice daily for 12 weeks. The study's 517 teenage volunteers were randomly assigned to one of the four treatments. Success was assessed as clear or almost clear skin at the end of the 12 week period. The results of the study can be seen in the table below. Using the appropriate statistical test, determine if there is significant evidence that the four treatments perform differently. If so, how do they compare.
A medical researcher is working on a new treatment for a certain type of cancer. Theaverage survival time after diagnosis on the standard treatment is two years. In an earlytrial, she tries the new treatment on three subjects who have an average survival timeafter diagnosis of six years. Although the survival time has tripled, the results are notstatistically significant even at the 0.10 significance level. The explanation isA) the placebo effect is present, which limits statistical significance.B) the sample size is small.C) that although the survival time has doubled, in reality the actual increase is reallytwo years.D) the calculation was in error. The researchers forgot to include the sample size.
Researchers examine the association between the fluoridation of water and the prevention of tooth decay by comparing the prevalence of tooth decay in countries that have fluoridated water with the prevalence in countries that do not. Is this a randomized experiment or an observational study? Assume that tooth decay was seen to be less common in countries with fluoridated water. Could this result be due to confounding?
On a trial basis, State College admitted 300 students from the lowest third of their high school graduation class. They were randomly divided into 3 groups. Group A received extensive training in study habits Group B received motivational lectures; and Group C received no special treatment. At the end of the year, the average grades of the groups were compared. Identify the following: * What is the Independent variable? * What is the Dependent variable? * Who is in the Experimental Group? * Who is in the Control Group? * What are at least 2 potential extraneous variables?
12) A professor wanted to compare the ages of male and female graduate students at her university. She collected a random sample of male and a random sample of female students in Spring 2022 semester. Data (in years) are given below. Is there sufficient evidence to conclude the difference in the means (average age) is statistically significant? use 5% (α = 0.05) significance level. Male graduate students: 29, 35, 36, 28, 24, 30, 31, 25, 27, 29, 41, 39, 38, 35, 30 Female graduate students: 28, 27, 29, 24, 28, 24, 35, 37, 26, 29, 28, 36, 28, 35, 28 a) Write the null hypothesis and alternative hypothesis to test the above claim. b) What is the value of the test statistic? c) What is the degrees of freedom of the t distribution of the test statistic? d) What is the p-value? e) Write your conclusion and express in terms of the evidence for the indicated calim.

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