Sta 3 chapter 3

Question: A 1958 amendment to the Food, Drugs, and Cosmetic Act of 1938 called the "Delaney Clause" has been instrumental in the banning of food additives since its enactment. Find the exact text of the one-sentence Delaney Clause. Which one of these is it?

... [T]he Secretary of the Food and Drug Administration shall not approve for use in food any chemical additive found to induce cancer in man, or, after tests, found to induce cancer in animals."

sing their left hands and six for a group using their right hands. Please use the data on page 65 to answer the following question: Question: What is the variance of the six Group R measurements? You will probably want to use a software package. The variance is the square of the standard deviation. See Chapter 2.

0.0013

tatistical science endeavors to answer the question "are treatment results different enough that they are unlikely to have occurred by chance?" If so, the results are said to be statistically significant. In another exercise you may have completed an activity where twelve reaction times were computed—six for a group using their left hands and six for a group using their right hands. Please use the data on page 65 to answer the following question: Question: What is the variance of the six Group L measurements? You will probably want to use a software package. The variance is the square of the standard deviation. See Chapter 2.

0.0030

unlikely to have occurred by chance?" If so, the results are said to be statistically significant. In another exercise you may have completed an activity where twelve reaction times were computed—six for a group using their left hands and six for a group using their right hands. Please use the data on page 65 to answer the following question: Question: What is the mean of the six Group R measurements?

0.1225

exercise you may have completed an activity where twelve reaction times were computed—six for a group using their left hands and six for a group using their right hands. Please use the data on page 65 to answer the following question: Question: What is the mean of the six Group L measurements?

0.1260

To complete the assignment, begin by reading Schmeck's article: http://www. nytimes.com/1981/03/12/us/study-links-coffee-use-to-pancreas-cancer.html. If this link does not work, search for the article under its title "Study Links Coffee Use to Pancreas Cancer," or by its author. Find the article, read it, and answer the following. What two groups were being compared in this experiment?

369 pancreatic cancer patients at 11 hospitals in the Boston metropolitan area were compared to 644 patients similar in age and sex who were hospitalized for reasons unrelated to the pancreas.

role that the Delaney Amendment had in Subway's decision. Find the CNN article by Elizabeth Landau about this issue. It has been available at this link: https://www.cnn.com/2014/02/06/health/subway-bread-chemical/index.html. (Links to an external site.) Why did Subway stop using azodicarbonamide in its breads?

It was found to cause cancers of the lung and blood vessels in mice.

Question: The hospital will more likely adopt a quasi-design that collects data for an extended period of time before hand cleaner dispensers are installed, and then compares those findings with data collected after the dispensers are installed. What are two possible sources of confounding with this design that the referenced article mentions?

Severity of patient illness and quality of medical care.

Coffee Use to Pancreas Cancer," or by its author. Find the article, read it, and answer the following. At least two other sources of circumstantial evidence were cited in the article as further support of a link between pancreatic cancer and coffee. Which one of the following is one of the two mentioned?

The apparent increase in frequency of cancer of the pancreas in the United States in recent decades, and the low rates observed in such groups as Mormons and Seventh Day Adventists, who do not drink coffee.

link does not work, search for the article under its title or by its author. Question: The article addresses amyotrophic lateral sclerosis (ALS), suggesting that mice studies might be misleading. The article gives two reasons why. What are they?

The fact that mice in the study tended to die from bowel cancer, unlike the humans who died from ALS and the lack of reproducibility in the mice studies.

Question: b. Aside from randomization issues, what is another possible source of confounding (other than lack of randomization) that might challenge a conclusion that exposure to music caused the L. A. students to do better.

The group in Orange County had both traditional and automated mathematics instruction (not just automated).

What is a "response variable? " Give an example not covered in the assigned reading. What is an " explanatory variable?" Give an example not covered in the assigned reading.

The response variable is the primary variable you are taking measurements on for your experiment, is the focus of the question in a study or experiment. An example is the subjects in an experiment The explanatory variable is what you are varying in your experiment, is the one that explains changes in that variable. An example is a thing that a subject would take or do in the experiment that causes change.

Question: How do you know that the subjects in this study could not have been randomized to the treatments that were compared? This was one of the more widely-reported studies that supported music training as positively impacting general academic performance.

The treatments were at two separate schools at two separate points in time.

Results [O]ur results indicate that there were no significant differences for post-test scores. Question: a. Looking at the information given in the Results section, why might you infer that in-class instruction is no better than online instruction?

There was no significant different in the post-test scores.

Question: Suppose a researcher suggests to place these cleaners in randomly chosen patient rooms and not in others. At the end of the study, the infection rates for each group could be compared. Why does the referenced paper say this simple design might be an impossible design to implement in practice?

To quote the paper, "it is difficult, politically, to implement use of an alcohol-based disinfectant only in certain parts of a hospital or only on certain sides of a ward."

Post-tests Instructors designed post-tests on a 100-point scale to test students' knowledge at the end of the course. The average post-test scores for online students was 77.80 (s.d. = 18.64). The average post-test scores for in-class students was 77.58 (s.d. = 16.93). Results [O]ur results indicate that there were no significant differences for post-test scores. Question: What is one obvious source of confounding that threatens the article's conclusion that online learning is no less effective than face-to-face learning?

no Students were not able to decide for themselves which course (online or face-to-face) they enrolled in. and No The pre-test scores of the two groups were identical, making it virtually impossible to say one type of class was better than the other.