Jack and Jill want to know whether running up a hill once a day improves lung capacity and decidedto conduct an experiment. Both Jack and Jill measured their lung capacity before the experiment.Through random allocation, it was decided that Jack would not exercise for six weeks while Jill ranup the hill once a day for the same six week period. At the end of six weeks, Jack and Jill againmeasured their lung capacity and compared the measure to the initial value for potentialimprovement. What key feature of a well-designed experiment did Jack and Jill not incorporate?(A) Random assignment of subjects to treatments(B) Replication within each treatment group(C) Stratifying by factors that affect the response variable(D) A control group for comparison(E) This experiment includes all key features of a well-designed experiment

Jack and Jill failed to incorporate the replication within each treatment group, so the correct…

Answered: Jack and Jill want to know whether…

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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You take a survey that is supposed to measure whether you are an extrovert or not. The score you get on the extrovert survey is a z-score of 2.0. What does that mean about your level of extraversion compared to the average score?
You conducted additional studies with these men and found the following: The RR for those who drank one drink per day was 1.50 (95% CI:1.32-1.67) in comparison to the abstainers. For those men who drank three or more drinks per day the RR compared to the abstainers was 4.20 (95% CI 2.68-5.85). Which one of Hill’s criteria does this illustrate? Explain.
Scientists are interested in the placebo effect on adults with arthritis. They randomly choose 15 adults with arthritis and give them 2 treatments: effective drug and placebo for 1 week at different times. At the end of each week, the scientists ask the participants to rate their arthritic pain level on a scale of 1-5, where 1 is little pain and 5 is a lot of pain. The researchers then take the difference of their pain levels (affective drug - placebo). The data are below. 0, 1, 2, 2, 0, -1, 3, 1, 2, -1, 0, 1, -2, -1, -6 (a) Find the 5-number summary for the difference of arthritic pain levels. Minimum = Q₁ = Median = USE SALT Q3 = Maximum = (b) One of the conditions for inference for population mean difference of paired data is normality. Outliers within a data set cast a shadow of doubt upon the normality of the population distribution. Use the 5-number summary calculated in part (a) to determine if there are any outliers in the data set. Which of the values, if any, is an outlier…
Some commercial airlines recirculate about half the air in the cabin during flights as a way to improve fuel efficiency. Other airlines make a policy of NOT recirculating the air and instead, have fresh air from the atmosphere constantly being inserted into the cabin with the “old” air being pumped out of the plane. A total of 1100 passengers flying from San Francisco to Denver were used for an experiment. After their flight, they were each given a list of symptoms associated with the common cold. They were asked to report if they experienced cold symptoms within 24 hours of the flight landing. Of the 517 passengers who flew on planes that recirculate the air, 108 reported post-flight cold symptoms. Of the 583 passengers who flew on airlines that do not use recirculation in the cabin, 110 reported symptoms. Suppose now that we want to use the recirculation of air data to explore “Goal #2”, which is to resolve a hypothesis test about . a) If we want to resolve this hypothesis…
Some commercial airplanes recirculate approximately 50% of the cabin air in order to increase fuel efficiency. The researchers studied 1100 airline passengers, among which some traveled on airplanes that recirculated air and others traveled on planes that did not recirculate air. Of the 515 passengers who flew on planes that did not recirculate air, 108 reported post-flight respiratory symptoms, while 112 of the 585 passengers on planes that did recirculate air reported such symptoms. Is there sufficient evidence to conclude that the proportion of passengers with post-flight respiratory symptoms differs for planes that do and do not recirculate air? Test the appropriate hypotheses using ? = 0.05. You may assume that it is reasonable to regard these two samples as being independently selected and as representative of the two populations of interest. (Use a statistical computer package to calculate the P-value. Use pdo not recirculate − pdo recirculate. Round your test statistic to two…
As the manager of a fashion brand, you have recently run a large-scale campaign to draw attention to your company's CSR activities and thus improve the brand's image. In order to evaluate the efficiency of the campaign, you conducted a survey at major fashion stores to measure the attitudes towards. your brand at two points of time: before the campaign started and after the campaign finished. By summing up respondents' answers to 3 questions (each measuring a particular aspect of attitude on a 1-5 scale), a single overall measure of attitude is obtained for each participant. This measure can therefore range from 3 to 15, with a score of 3 representing and extremely negative attitude and a score of 15 representing an extremely positive attitude. To check whether male and female customers have different attitudes towards you company, as well as to test whether the campaign may have affected males and females differently, you ask the respondents to report their gender. You analyse the…
whether cross-sectional, retrospective, or prospective is used. Rats with cancer are divided into two groups. One group receives 5 mg f mediation that is thought to fight cancer, and the other receives 10 mg. After 2 years, the spread of the cancer is measured.
Can a person train to become better at holding their breath? An experiment was designed to find out. Twelve volunteers were randomly assigned to 1 of 2 groups. The 6 volunteers assigned to group 1 were given breath-holding exercises to perform for 2 weeks. The other group was not given any information about the experiment. At the end of the 2 weeks, all 12 volunteers were individually tested to determine how long they could hold their breath. Here are the data (in seconds). Group 1: 90, 88, 70, 110, 75, 105 Group 2: 40, 48, 35, 50, 55, 62 The researcher would like to determine if these data provide convincing evidence that the true mean amount of time volunteers who were given training held their breath is greater than volunteers without training. Let ₁ = the true mean amount of time that volunteers who were given training held their breath and ₂ = the true mean amount of time that volunteers without training held their breath. What are the appropriate hypotheses? Ho: U1 - U2 = 0, Ha:…
Elaine is interested in determining if men are more satisfied in their jobs than women in the healthcare industry. She administers a job satisfaction questionnaire to 20 men and 20 women working in hospital administration. Her grouping variable is gender and dependent variable is job satisfaction. The job satisfaction scale consists of 8 items measured using a 5-point rating scale. A higher score on this scale would indicate high job satisfaction. The maximum score that can be obtained on the scale is 40. We can assume that job satisfaction scores are normally distributed. Use the appropriate T test with a significance level of 0.05 to test the hypothesis. Research Question Do the mean job satisfaction scores differ for men and women working in the hospital administration department? Hypothesis The mean job satisfaction scores do not differ for men and women working in the hospital administration department. Compute an independent sample t test on these data. Report…
A traffic office in a country was in charge of a study where the safety of passengers in different types of cars was examined. Three models were examined; small cars, minivans and SUVS and six cars in each category were inspected. A special traffic accident simulator was used in the study and the pressure on the drivers' heads was measured. Umferðarastofa wanted to investigate whether there was a difference in the average pressure on the head during a collision in these three types of cars and used a variance analysis for this purpose. Failed to complete the square sum table, which can be seen below. weekend sum degree of freedom ave week sums between groups (area) 725.4 within groups (area) 178.6 XXX total Questions 1-3 deal with this study by the Traffic Authority. Question 1 What value should be given where xxx is in the table? 1 1.91 2. 2679 3. 3036.2 4. The information provided cannot be answered. Question 2 to be used to check if there is a difference in the average- What is the…
Denny studied factors affecting cardiovascular reactivity to a postural change in a sample of healthy men and women. Change in systolic blood pressure (SBP) from supine to standing position was used as the measure of cardiac reactivity in a sample of 842 adults. Supine measurement of blood pressure was taken after participants had lain on an examination table for 15 minutes. Blood pressure was determined every 30 seconds using a Dinamap device for 2 minutes, and the measurements were averaged. Participants then stood up immediately, and additional measurements were made for another 2 minutes. Below is a table describing the characteristics of Denny’s sample: Which measures of dispersion, if any, are presented in this table (Ranges, SDs)? If age is normally distributed, approximately what percent of the sample would be younger than 50? If BMI is normally distributed, approximately what percent of the sample would have a BMI higher than 33.1?
Jane measures the age of death of 4 strains of mice using 40 male mice per strain, with 20 mice from each strain on a high protein diet and the other 20 mice on a high fat diet. What is the N (the number of independent observations) in this experiment? Draw the experimental design table.

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