sto ave 12.72 (M4) The authors of the paper "Serum Zinc Levels of Cord Blood: Relation to Birth Weight and Gestational Period" (Journal of Trace Elements in Medicine and Biology [2015]: 180-183) car- ried out a study of zinc levels of low-birth-weight babies and normal-birth-weight babies. For a sample of 50 low- birth-weight babies, the sample mean zinc level was 17.00 and the standard error was 0.43. For a sample of 73 normal-birth-weight babies, the sample mean zinc level was 18.16 and the standard error was 0.32. Explain why the two standard errors are not the same.

The vulnerability of inshore environments to contamination due to urban and industrial expansion in Mombasa is discussed in the paper €œMetals, Petroleum Hydrocarbons and Organo-chlorines in Inshore Sediments and Waters on Mombasa, Kenya€ [Marine Pollution Bulletin (1997) 34: 570€“ 577]. A geochemical and oceanographic survey of the inshore waters of Mombasa, Kenya, was undertaken during the period from September 1995 to January 1996. In the survey, suspended particulate matter and sediment were collected from 48 stations within Mombasa€™s ­estuarine creeks. The concentrations of major oxides and 13 trace elements were determined for a varying number of cores at each of the stations. In particular, the lead concentrations in suspended particulate matter (mg kg-1 dry weight) were determined at 37 stations. The researchers were ­interested in determining whether the average lead concentration was greater than 30 mg kg-1 dry weight. The data are given in the following table along with…

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?

Seedlings of understory trees in mature tropical rainforests must survive and grow using inter- mittent flecks of sunlight. How does the length of exposure to these flecks of sunlight (fleck duration) affect growth? Leakey et al. (2005) experimentally irradiated seedlings of the Southeast Asian rainforest tree Shorea leprosula with flecks of light of varying duration while maintaining the same total irradiance to all the seedlings. Their data for 21 seedlings are listed in the following table.  i. What is the rate of change in relative growth rate per minute of fleck duration? provide a standard error for your estimate. ii. using these data, test the hypothesis that fleck duration affects seedling growth rate. iii. Calculate a 99% confidence interval for the slope of the population regression.

5.33 The paper "Predictors of Complementary Therapy Use Among Asthma Patients: Results of a Primary Care Survey" (Health and Social Care in the Community [2008]: 155–164) described a study in which each person in a large sample of asthma patients responded to two questions: Question 1: Do conventional asthma medications usu- ally help your symptoms? Question 2: Do you use complementary therapies (such as herbs, acupuncture, aroma therapy) in the treat- ment of your asthma? i. The probability that an asthma patient responds that conventional medications do not help and that the patient uses complementary therapies. ii. The probability that an asthma patient responds that con- ventional medications do not help and that the patient does not use complementary therapies. iii. The probability that an asthma patient responds that conventional medications usually help or the patient uses complementary therapies. Suppose that this sample is representative of asthma patients. Consider the…

During the spring of 1999, many fuel storage facilities in Serbia were destroyed by bombing. As a result, significant quantities of oil products were spilled and burned,resulting in soil pollution. The article “Mobility of Heavy Metals Originating from Bombing of Industrial Sites” (B. Škrbić, J. Novaković, and N. Miljević, Journal of Environmental Science and Health, 2002:7–16) reports measurements of heavy metal concentrations at several industrial sites in June 1999, just after the bombing, and again in March of 2000. At the Smederevo site, on the banks of the Danube River, eight soil specimens taken in 1999 had an average lead concentration (in mg/kg) of 10.7 with a standard deviation of 3.3. Four specimens taken in 2000 had an average lead concentration of 33.8 with a standard deviation of 0.50. Find a 95% confidence interval for the increase in lead concentration between June 1999 and March 2000.