6. How safe are anesthetics? (3.1, 3.6) The National Halothane Study was a major investigation of the safety of anesthetics. Performed in 34 major hospitals, the study showed the following death rates for four common anesthetics: Anesthetic Death rate A 1.7% B 1.7% C 3.4% D 1.9% There seems to be a clear association between the anesthetic used and the death rate of patients. Anesthetic C appears to be more dangerous.104 more A) Explain why we call the National Halothane Study an observational study rather than an experiment, even though it compared the results of using different anesthetics in actual surgery. B) When the study looked at other variables that are related to a doctor's choice of anesthetic, it found that Anesthetic C was not causing extra deaths. Explain the concept of confounding in this context and identify a variable that might be confounded with the doctor's choice of anesthetic.

Using age as the quantitative variable and marital status (married/not married) as the categorical. Develop two research questions.

ed weight (in kg) and total serum cholesterol (TSC in mg/dl) data for five men (n = 5). They tested for association between weight and TSC at 5% level of significance. weight, X TSC, Y X*X Y*Y X*Y 37 2.9 1369 8.41 107.3 50 0.7 2500 0.49 35.0 67 3.3 4489 10.89 221.1 70 4.2 4900 17.64 294.0 57 3.8 3249 14.44 216.6 SUM: 281 14.9 16507 51.87 874.0 What are the Null and Alternate hypotheses for this test? Clearly label your answers as HỌ or H1. (Do not use a numerical format. Both of your statements must be in sentence form, and say something about the weight

For the following data 4,4,6, 10 o = 2.4 Then C.V.= Select one: O a. 25% O b. 47% Ос. 22.4% d. 40%

Aspirin III: Decision and Conclusion Regarding the experiment in the data frame Aspirin from the abd package, the researchers wanted to know whether or not taking aspirin affects one's risk of developing cancer. Recall that they defined their parameters as follows: p1 = the proportion of ALL individuals who would develop cancer, if all of them were to take aspirin like the subjects in the Aspirin group did. p2 = the proportion of ALL individuals who would develop cancer, if all of them were to take a placebo, like the subjects in the placebo group did. They ran the code for a two-sided significance test and got the following results: ## ## ## Inferential Procedures for the Difference of Two Proportions p1-p2:##   cancer grouped by treatment ## ## ## Descriptive Results:## ##          yes     n estimated.prop## Aspirin 1438 19934        0.07214## Placebo 1427 19942        0.07156## ## ## Inferential Results:## ## Estimate of p1-p2:    0.0005805 ## SE(p1.hat - p2.hat):  0.002586 ## ##…

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Johnson and Leone describe an experiment to investigate the warping of copper plates. The two factors studied were temperature and the copper content of the plates. The response variable was a measure of the amount of warping. The data are as follows: Temperature (°C) 50 75 100 Copper Content (%) 40 60 80 100 17 20 12 9 16 12 21 17 21 16 24 21 18 13 18 21 ZZFEHERRE 23 22 27 17 27 31 30 23 29 31 12 25 23 23 28 22 125 Source: Applied Statistics and Probability for Engineers, 6th Edition, Douglas, C. Montgomery & George, C. Runger. 1. Draw and interpret the interaction plot. ii. Is there any significant interaction between the factors? Use a = 0.05. ii. Can your interpretation in (i) be validated in (ii)? Twelve plants are randomly

1. Effect size and Cohen's D: a. What is an effect size? What info does it tell you, when is it calculated, etc.? b. What is Cohen’s d? What info does it tell you about the independent variable and dependent variable? (think of how you write the sentences explaining your numbers)

What is the difference between an observational study and an experiment? Choose the correct answer below. O A. In an experiment, a treatment is applied to part of a population and responses are observed. In an observational study, a researcher measures characteristics of interest of a part of a population but does not change existing conditions. O B. In an experiment, a researcher measures characteristics of interest of an entire population but does not change existing conditions. In an observational study, a treatment is applied to an entire population and responses are observed. O C. In an experiment, a treatment is applied to an entire population and responses are observed. In an observational study, a researcher measures characteristics of interest of an entire population but does not change existing conditions. O D. In an experiment, a researcher measures characteristics of interest of a part of a population but does not change existing conditions. In an observational study, a…