"Does ginkgo improve memory?" The law allows marketers of herbs and other natural substancesto make health claims that are not supported by evidence. Brands of ginkgo extract claim to "improve memoryand concentration." A randomized experiment found some statistically significant evidence for such effects.The subjects were 250 healthy volunteers over 65 years old. They were randomly assigned to take ginkgo or aplacebo pill (a dummy pill that looks and tastes the same). All the subjects took a battery of tests for learningand memory before treatment started and again after six weeks.a). The article said the study was double-blind. What does this mean in the context of this study? Be veryspecific on who's being blinded and explain why they should be blinded.b). You suspect physical fitness and mental fitness go hand-in-hand. Create a flow chart to describe a designfor an experiment to include the confounding variable physical fitness. Be very specific in your design.Include all details such as: Will blocking be used? If yes, who ill be in each block? When will you performrandom assignment? etc.

Cause and effect: The relationship between events where one results in the other. The outcome of…

Answered: "Does ginkgo improve memory?" The law…

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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Exercise is known to produce positive psychological effects. Interestingly, not all exercise is equally effective. It turns out that exercising in a natural environment (e.g., jogging in the woods) produces better psychological outcomes than exercising in urban environments or in homes (Mackay & Neill, 2010). Suppose that a sports psychologist is interested in testing whether there is a difference between exercise in nature and exercise in the lab with respect to post-exercise anxiety levels. The researcher recruits n 5 7 participants who exercise in the lab and exercise on a nature trail. The data below represent the anxiety scores that were measured after each exercise session. Treat the data as if the scores are from an independent-measures study using two separate samples, each with n 5 7 participants. Compute the pooled variance, the estimated standard error for the mean difference, and the independent-measures t statistic. Using a 5 .05, is there a significant difference…
The Wisconsin Fish and Game Department stocked a lake with 30% catfish, 15 % bass, 40% bluegill, and 15% Northern Pike. Five years later they took a random sample of 500 fish from the lake and found 120 catfish, 85 bass, 220 bluegill, and 75 Northern Pike. At the 5% level of significance, can we show that the distribution of fish changed over the 5-year interval? State and test appropriate hypotheses. State conclusions.
Researchers investigate how the presence of cell phones influence the quality of human interaction. Subjects are randomly selected from a population and divided into an experimental group that is asked to leave their phones in the front of the room and a control group that are not asked to leave their cell phones at the front of the room. Subjects are left alone for 10 minutes and then asked to take a survey designed to measure quality of interactions they had with others in the experiment. What statistical test is appropriate?
Although there is a popular belief that herbal remedies such as Ginkgo biloba and Ginseng may improve learning and memory in healthy adults, these effects are usually not supported by well-controlled research (Persson, Bringlov, Nilsson, and Nyberg, 2004). In a typical study, a researcher obtains a sample of n = 16 participants and has each person take the herbal supplements every day for 90 days. At the end of the 90 days, each person takes a standardized memory test. For the general population, scores from the test form a normal distribution with a mean of u = 50 and a standard deviation of o = 12. The sample of research participants had an average of M = 54 . a. Assuming a two-tailed test, state the null hypothesis in a sentence that includes the two variables being examined. b. Using the standard 4-step procedure, conduct a two-tailed hypothesis test with a = .05 to evaluate the effect of the supplements.
Homechooling has become very popular in the United States, and many colleges try to attract students from this group. Evidence suggests that approximately 90% of all homeschooled children attend college. To check this claim, a random sample of 208 homeschooled children was obtained, and 180 of them were found to have attended college. The researcher wishes to determine whether the proportion of homeschool children who attend college is different from 0.90. Test an appropriate hypothesis and state your conclusion. Make sure to state and check all conditions and state your conclusion in context.
A team of epidemiologists at the Mayo Clinic wanted to find whether there is an association between obesity and cardiovascular disease (CVD). They conducted a prospective cohort study following obese and non-obese individuals who were free of CVD at the beginning of study for five years. The investigators were also interested in assessing age as a potential confounder, effect modifier, or both. Use the data below to answer the accompanying questions. CVD No CVD Total Obese 10 90 100 Not Obese 35 465 500 Total 45 555 600 CVD No CVD Total Obese 36 164 200 Not Obese 25 175 200 Total 61 339 400 1. Compute the appropriate measure of association for those who were less than age 50. 2. Compute the appropriate measure of association for those who were older or equal to age 50. 3. Compute the crude measure of association? 4. List three attributes that age must satisfy before it could…
In 1972, half of a group of 111 low-income children from Chapel Hill, NC were randomly chosen for enrollment in an intensive pre-school program, while the other half were not enrolled in any preschool program. 30 years later the preschool group had a higher % attending college, higher average GPA for those who did attend college, and higher average wages than the non-preschool group. Fill in the following table. Is there a control treatment (and, if so, what is it)? Is there any accounting for individual variation? Is there repetition in the experiment? Is the experiment reproducible? Can we say with some confidence that preschool has some lasting effects on career outcomes?

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