Biology 2244A/B Chapter Notes - Chapter 8: Null Hypothesis, Simple Random Sample, Confidence Interval

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15 Mar 2015

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Using sample data to compare two population proportions. Requirements: have proportions form 2 simple random samples that are independent. Sample values selected from one population are not related. Notation: for population 1 we let: p1 = population proportion n1 = size of sample taken from population 1 x1 = number of successes in the sample taken from population 1 x1 n1. Q 2 = 1 - p 2 (the sample proportion) Finding the numbers of successes x1 & x2: x1 = n1 p 1, x2 = n2 p 2, ex. When 734 men were treated with viagra, 16% of them experienced headaches n1 = 734. P 1 = 0. 16 x1=734 0. 1 6 = 117. 44 117. Testing only claims that p1 = p2. Use the pooled (or combined) estimate of the value that p1 and p2 have in common. Interval estimate of the difference between population proportions (p1-p2)

Related Questions

1. The risk of acquiring disease is measured by the a. Incidence rate b. Incidence rate times the average duration of the disease c. Incidence rate divided by the prevalence rate d. Prevalence rate e. Prevalence rate times the average duration of the disease

2. The strength of an association between a factor and a disease is best measure by a. Incubation rate b. Incidence of the disease in the total population c. Prevalence of the factor d. Attributable risk e. Relative risk

3. Case fatality rate for a given disease refers to a. The crude mortality rate per 100,000 population b. Cause-specific mortality rate due to the disease c. A fatal outcome of any disease d. The percentage of deaths among cases of the disease e. The proportion of deaths due to the disease among all deaths from all causes

4. An investigator is interested in etiology of neonatal jaundice. To study this condition, he selected 100 children who were diagnosed with this condition and 100 children born in the same period and in the same hospital who did not have a diagnosis of neonatal jaundice. He then reviewed the obstetrical and delivery records of their mothers to determine various prenatal and perinatal exposures. This is an example of a(n): a. Cross-sectional study b. Case-control study c. Cohort study d. Clinical trial e. Experiment

5. Which of the following statements describes the major advantages of a randomized clinical trial? a. It avoids observer bias b. It lends itself to ethical justification c. It yields results replicable in other patients d. It rules out self-selection of participants to the different treatment groups d. It enrolls representative patients

6. A survey conducted in England revealed that of 224 families in which there had been a known case of poliomyelitis, 56 maintained parakeets as a family pet. In another British survey, 30 out of 99 poliomyelitis patients questioned kept parakeets. The inference that there is some relationship between the presence of a parakeet in a household and the occurrence of poliomyelitis among household members is a. Correct b. Incorrect because of failure to distinguish between incidence and prevalence c. Incorrect because a proportionate ratio is used when a rate is required to support the inference d. Incorrect because a failure to recognize a possible cohort phenomenon e. Incorrect because there is no control or comparison group.

7. An investigator determines the correlation coefficient between triglyceride levels and degree of atherosclerosis in sampled blood vessels to be +1.67. On the basis of this you would conclude that: a. Triglyceride level is a good predictor of atherosclerosis b. Triglyceride level is not a good predictor of atherosclerosis c. High triglyceride levels cause atherosclerosis d. Atherosclerosis cause high triglyceride levels e. The investigator has incorrectly determined the correlation coefficient

8. A screening test of known sensitivity and specificity is applied to two populations. The prevalence of the disease being screened for is 10% in population A and is 1% in population B. Which of the following is true? a. The percent of all negative tests that have false-negative results is lower in population A than in population B. b. Specificity is lower in population A than in population B. c. Reliability is higher in population A than in population B. d. The percent of all positive tests that have false-positive results is lower in population A than in population B. e. Specificity is higher in population A than in population B.

9. Serum cholesterol levels are obtained for four healthy men. The probability that all will fall below the 10th percentile of the distribution of cholesterol for healthy males is: a. 0.4 b. 1 â (0.1)4 c. (0.1)4 d. (0.9)4 e. Cannot be determined from these data

10. In a diabetes screening program, the screening level for a positive blood sugar level in test 1 is set at 160 mg/dl, and in test 2 at 130 mg/dl. The sensitivity is: a. Greater in test 1 b. Greater in test 2 c. Equal in test 1 and 2 d. Dependent on the size of the population being evaluated

Part II 1.The California Occupational Mortality study data set was employed to assess mortality data for the years 1979-1981. A 2% sample of employed persons from the 1980 census of California was used. It contains the occupation of each person who had died. This study, like any occupation-based study, is restricted to the work life span as far as age of subjects is concerned. This study used ages 16-64 years. Certain persons, because of their source of work, were excluded as subjects: homemakers, retired persons, students, disabled, military personnel, etc. Only main-stream-type employment was used in this study to establish occupations at risk for heavy alcohol drinking. Using the Table below, answer the following:

1.What occupations are most vulnerable to acquiring cirrhosis of the liver from heavy drinking?

2.List several of the occupations identified by the research studies that are more vulnerable to alcohol-induced, cirrhosis related deaths and that have the highest mortality rates.

3. What are possible confounding variables for the research in occupations and heavy drinking that lead to fatal diseases?

4. Based on available research data, develop and construct a web of causation along with the appropriate decision trees for occupational group-related alcohol deaths. Table. Alcohol Related Deaths in California, 1979-1981 Cirrhosis 5.5% Digestive organ cancers 5.7% Injuries 13.7% Suicide and homicide 5.% All other causes 64.9%

Zika and microcephaly Since May 2015, Brazil has experienced a significant outbreak of Zika virus. In recent years, Brazilian officials reported an increase in the number of babies born with microcephaly.

1. Briefly describe what we know and what we do not know about Zika virus.

2. What has been done and what should be done to prevent Zika virus epidemic in US and world-wide?

Recently I have found myself in a discussion with a guy thatisn't a creationist, but denies evolution. He cites several studiesthat show problems like this one, but I do not have the knowledgeto refute it properly. Whats the problem with the following:

One problem is that population genetics shows us evolutiondestroys functional sequences much faster than it creates them inany large-genome animal with low reproductive rates, becausedeleterious mutations arrive faster than selection can remove them.This would include just about all mammals, reptiles, and birds--anyof our would-be ancestors over the last 300m years.

Specifically, humans get 60 to 160 mutations per generation,10-20+% of our genome is sensitive to substitution, and this givesus 6-32 deleterious mutations per offspring (most slight). Evenwith the low estimate of 6, every child is less fit than theirparents and natural (or even artificial) selection can only choosethe least degenerate each generation. For every generation where amutation can be selected, random mutations destroy 5-32+ previouslyselected. Beneficial mutations like lactose tolerance (a jammedswitch) take 1000s of years to appear and fixate.

If you know the genome size, mutation rate, and reproductiverate, you can calculate at what rate deleterious mutations arrivefaster than they can be removed:

"It has been estimated that there are as many as 100 newmutations in the genome of each individual human. If even a smallfraction of these mutations are deleterious and removed byselection, it is difficult to explain how human populations couldhave survived. If the effects of mutations act in a multiplicativemanner, the proportion of individuals that become selectivelyeliminated from the population (proportion of `genetic deaths') is1-e^-U, where U is the deleterious mutation rate per diploid, so ahigh rate of deleterious mutation (U>>1) is paradoxical in aspecies with a low reproductive rate." High genomic deleteriousmutation rates in hominids, (Nature, 1999)

They worry about a deleterious rate of U much greater than 1 asbeing prohibitively high and we're talking about it being 6-32+,since we now know the functional genome is much larger than wethought it was in 1999. Taking their Poisson probabilitydistribution and using U=6, that means 1-e^-6 = 99.752% of thepopulation will have to be selected away each generation for onelucky enough to have no deleterious mutations. For two to surviveand maintain constant population size that would require on average806 offspring per female--impossible for most mammals, birds, andreptiles. Actually much more since natural selection is notomnisciently efficient.

Discussion: Assessing the Ears, Nose, and Throat Most ear, nose, and throat conditions that arise in non-critical care settings are minor in nature. However, subtle symptoms can sometimes escalate into life-threatening conditions that require prompt assessment and treatment. Nurses conducting assessments of the ears, nose, and throat must be able to identify the small differences between life-threatening conditions and benign ones. For instance, if a patient with a sore throat and a runny nose also has inflamed lymph nodes, the inflammation is probably due to the pathogen causing the sore throat rather than a case of throat cancer. With this knowledge and a sufficient patient health history, a nurse would not need to escalate the assessment to a biopsy or an MRI of the lymph nodes, but would probably perform a simple strep test. In this Discussion, you consider case studies of abnormal findings from patients in a clinical setting. You determine what history should be collected from the patients, what physical exams and diagnostic tests should be conducted, and formulate a differential diagnosis with several possible conditions. Note: By Day 1 of this week, your instructor will have assigned you to one of the following case studies to review for this Discussion. Also, your Discussion post should be in the SOAP Note format, rather than the traditional narrative style Discussion posting format. Refer to Chapter 2 of the Sullivan text and the Comprehensive SOAP Template in the Week 4 Learning Resources for guidance. Remember that not all comprehensive SOAP data are included in every patient case. Case 1: Nose Focused Examination Richard is a 50-year-old male with nasal congestion, sneezing, rhinorrhea, and postnasal drainage. Richard has struggled with an itchy nose, eyes, palate, and ears for 5 days. As you check his ears and throat for redness and inflammation, you notice him touch his fingers to the bridge of his nose to press and rub there. He says he's taken Mucinex OTC the past two nights to help him breathe while he sleeps. When you ask if the Mucinex has helped at all, he sneers slightly and gestures that the improvement is only minimal. Richard is alert and oriented. He has pale, boggy nasal mucosa with clear thin secretions and enlarged nasal turbinates, which obstruct airway flow but his lungs are clear. His tonsils are not enlarged but his throat is mildly erythematous. To prepare: Review this week's Learning Resources and consider the insights they provide. Consider what history would be necessary to collect from the patient. Consider what physical exams and diagnostic tests would be appropriate to gather more information about the patient's condition. How would the results be used to make a diagnosis? Identify at least 10 possible conditions that may be considered in a differential diagnosis for the patient. Note: Before you submit your initial post, replace the subject line (âWeek 5 Discussionâ) with âReview of Case Study ___,â identifying the number of the case study you were assigned. Post a description of the health history you would need to collect from the patient in the case study to which you were assigned. Explain what physical exams and diagnostic tests would be appropriate and how the results would be used to make a diagnosis. List five different possible conditions for the patient's differential diagnosis and justify why you selected each.

Biology 2244A/B Chapter Notes - Chapter 8: Null Hypothesis, Simple Random Sample, Confidence Interval

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