24. People with an autoimmune disease like lupus produce antibodies that react to their own tissues. Research has shown that lupus-prone strains of mice have B cells with redudd expression levels of the receptor gene SYRIIB, suggesting that low expression of this gene might contribute to the autoimmune reaction. To test this, McGaha et al. (2005) experimentally enhanced expression of the FcyRIIB gene in bone marrow taken from a lupus-prone mouse strain and transplanted it back into irradiated mice of the same strain. Other mice of the same strain were subjected to the same procedures but received bone marrow that was not enhanced for FcyRIIB expression (i.e., the sham treatment). Mice in a third group were left untreated. Auto- immune reactivity was measured six months later. The following is a frequency table indi- cating the highest dilution of blood serum, in a fixed series of dilutions, at which reactivity could be detected (a high dilution reflects a high autoimmune reactivity).

27. Lower Limb Surgery. The study "Intrathecal Sufentanil ver- sus Fentanyl for Lower Limb Surgeries- A Randomized Controlled Trial" (Journal of Anaesthesiology Clinical Pharmacology, Vol. 27, Issue 1, pp. 67-73) by P. Motiani et al. compares two different agents, intrathecal sufentail and fentanyl, used in enhancing the anesthesiol- ogy of patients receiving major lower limb surgery. One variable com- pared between the two agents was the amount of blood loss during the surgery. Based on the study, we will assume that, using fentanyl, the amount of blood loss during major lower limb surgery is normally distributed with mean 283.3 ml and standard deviation 83.3 ml. Find the percentage of patients whose amount of blood loss during major lower limb surgery using fentanyl is a. less than 304 ml. b. between 221 and 429 ml. c. more than 450 ml.

According to a certain government agency for a large country, the proportion of fatal traffic accidents in the country in which the driver had a positive blood alcohol concentration (BAC) is 0.38. Suppose a random sample of 112 traffic fatalities in a certain region results in 52 that involved a positive BAC. Does the sample evidence suggest that the region has a higher proportion of traffic fatalities involving a positive BAC than the country at the α = 0.1 level of significance? Because npo (1-Po) = (Round to one decimal place as needed.) What are the null and alternative hypotheses? 10, the sample size is Ho: versus H₁: (Type integers or decimals. Do not round.) Find the test statistic, Zo. Find the P-value. P-value = Zo (Round to two decimal places as needed.) = the requirements for testing the hypothesis 5% of the population size, and the sample satisfied. (Round to three decimal places as needed.)

A large randomized trial was conducted to assess the efficacy of Chantix for smoking cessation compared with bupropion (more commonly known as Wellbutrin or Zyban) and a placebo. Chantix is different from most other quit‑smoking products in that it targets nicotine receptors in the brain, attaches to them, and blocks nicotine from reaching them, while bupropion is an antidepressant often used to help people stop smoking. Generally healthy smokers who smoked at least 1010 cigarettes per day were assigned at random to take Chantix ( ?=352n=352 ), bupropion ( ?=329n=329 ), or a placebo ( ?=344n=344 ). The response measure is continuous cessation from smoking for Weeks 99 through 1212 of the study. A two‑way table of the results is given.                                                          Treatment                                              Chantix    Bupropion  Placebo No smoke in weeks 9-12       155             97             61 Smokes in weeks 9-12            197            232…

A large randomized trial was conducted to assess the efficacy of Chantix for smoking cessation compared with bupropion (more commonly known as Wellbutrin or Zyban) and a placebo. Chantix is different from most other quit-smoking products in that it targets nicotine receptors in the brain, attaches to them, and blocks nicotine from reaching them, while bupropion is an antidepressant often used to help people stop smoking. Generally healthy smokers who smoked at least 10 cigarettes per day were assigned at random to take Chantix (n = 352), bupropion (n 329), or a placebo (n = 344). The response %3| measure is continuous cessation from smoking for Weeks 9 through 12 of the study. A two-way table of the results is given. Treatment Chantix Bupropion Placebo No smoking in Weeks 9-12 155 97 61 Expand Smoked in Weeks 9-12 197 232 283 To access the complete data set, click the link for your preferred software format: Excel Minitab JMP SPSS TI R Mac-TXT PC-TXT CSV CrunchIt! STATE: How does…

The results of a multicenter clinical trial to determine the safety and efficacy of the pancreatic lipase inhibitor, Xenical, was reported (Ingersoll, 1997). Xenical is used to block the absorption of dietary fat. The article reported that more than 4000 patients in the U.S. and Europe were randomized to receive Xenical or a placebo in a parallel groups study. After one year, 57% of those receiving Xenical had lost at least 5% of their body weight, as opposed to 31% of those receiving a placebo. Assume that exactly 4000 patients were in the study, and that 2000 were randomized to receive a placebo and 2000 received Xenical. Please Compute a 95% confidence interval for the “relative risk” of losing at least 5% of body weight for those receiving Xenical relative to those receiving placebo. Can the drug be considered effective?

Sickle-cell anemia is a hereditary chronic blood disease that is extremely severe when an individual carries two copies of the defective gene. It is particularly common in countries plagued by malaria, a parasiticinfection transmitted by mosquitoes. A study in Africa tested 543 children for the sickle-cell gene and also for malaria. In Group 1 which consisted of 136 children with the sickle-cell gene, 36 children had severe malariainfections. Group 2 consisted of 407 children without the sickle-cell gene, and 152 of them had severe malaria infections. Conduct a test to determine if the proportion of severe malaria infections among children withthe sickle-cell trait is different from that among children without. Test at 5% level of significance. Question: What is your p value and t statistic ?

I have a random sample of data on university students and I want to estimate the following model for first-year student academic performance at university: WAM = β0 + β1faminc + β2ATAR + β3attend + u where WAM = a student's weighted average mark at the end of the first year faminc = a student's family income in $000s ATAR = a student’s university entry score (0-100) attend = the proportion of classes the student attended in their first year I want to estimate the causal effect of class attendance (attend) on WAM.  I am concerned there is an omitted variable z that I cannot get data on but I believe it belongs in the model. It is well known that z has a positive effect on WAM and that z is negatively related to class attendance (attend). To answer this question, please assume that ATAR and faminc are both uncorrelated with attend and are both uncorrelated with z. If I estimate the model above without including the variable z, then I can expect that: a) β^3 will be negatively biased…

7/8) individuals tend to vary in their taste sensitivity. Is it possible that this trait may be linked to a person’s genetics? A scientist identified the genotype of 30 individuals for a gene she believes to be responsible for taste sensitivity. She compares taste sensitivity across the homozygous dominant, heterozygous, and homozygous recessive individuals. Q) What is the explanatory variable here? Q) What kind of variable is the subject’s genotype?

A number of studies have examined how alcohol consumption affects neuroticism using an animal model.  Two kittens are randomly selected from each of 7 litters (two cats from each litter).  One cat from each pair is assigned to the experimental group which is subjected to a procedure that induces temporary neurosis. The other cat from each pair is part of the control group (no neurosis induction). All the cats are then offered milk spiked with 5% alcohol.  The amount of milk consumed in three minutes is measured (in milliliters). Do the kittens in the experimental group drink more alcohol than the kittens in the control group?   What test should you use and why?