Which research design studies only people who are initially free of the disease of interest? Explain how this study design is different from the rest of the research designs

The term clinical means that the study involves people.  True  False

Identifying individuals with a high risk of Alzheimer’s disease usually involves a long series of cognitive tests. However, researchers have developed a 7-Minute Screen, which is a quick and easy way to accomplish the same goal. The question is whether the 7-Minute Screen is as effective as the complete series of tests. To address this question, Ijuin et al. (2008) administered both tests to a group of patients and compared the results. The following data represent results similar to those obtained in the study. Scores in 7minute-screen (Y) Scores in Cognitive series (X) 0 11 4 19 6 22 8 20 5 14 4 13 A) Calculate the Pearson correlation for these data. B) If the researchers centered the variable of 7-minute screen (i.e., every score in this variable minus its Mean), what would be the new value of correlation? C) Is the correlation statistically significant? Use a two-tailed test with α = .05.

In which of these research designs would you have complete control of the environment?     Cohort     Cross-sectional     Experimental     Case-Control

Researchers investigate how the presence of cell phones influence the quality of human interaction.  Subjects are randomly selected from a population and divided into an experimental group that is asked to leave their phones in the front of the room and a control group that are not asked to leave their cell phones at the front of the room.  Subjects are left alone for 10 minutes and then asked to take a survey designed to measure quality of interactions they had with others in the experiment.  What statistical test is appropriate?

NCI Cancer Bulletin, December 2, 2008 Volume 5 / Number 24 Title of the article: After Menopause, Weight Affects Breast Cancer Rates More than Mammography Use   Women who are overweight or obese after menopause face an increased risk of breast cancer, but a large prospective cohort study indicates that the frequency of mammography use and screening accuracy are not the primary explanations for higher rates of breast cancer in these women. The same is true of large, invasive breast cancer tumors and advanced stage disease; risk increases with weight, but higher rates are not explained by the frequency or accuracy of screening mammography before breast cancer was diagnosed. The study appears in the December 3 Journal of the National Cancer Institute.   Dr. Karla Kerlikowske of the San Francisco Veterans Affairs Medical Center and colleagues gathered data on 287,115 postmenopausal women who were registered in the Breast Cancer Surveillance Consortium database. Reflecting a trend in the…

Using the latest in medical technology, an orthopedic doctor has developed a new surgical procedure that he believes is an improvement over the standard procedure. He wants to study whether the mean recovery time of patients who have the new procedure is less than the mean recovery time of patients who have the standard procedure. The doctor studies a random sample of 11 patients who have the new procedure and a random sample of 9 patients who have the standard procedure. (These samples are chosen independently.) The doctor records each patient's recovery time (in days). The patients who had the new procedure have a sample mean recovery time of 367.3 with a sample variance of 2851.8. The patients who had the standard procedure have a sample mean recovery time of 420.9 with a sample variance of 98.1. Assume that the two populations of recovery times are approximately normally distributed. Can the doctor conclude, at the 0.01 level of significance, that the population mean of the…

Identifying individuals with a high risk of Alzheimer's disease usually involves a long series of cognitive tests. However, researchers have developed a 7-Minute Screen, which is a quick and easy way to accomplish the same goal. The question is whether the 7-Minute Screen is as effective as the complete series of tests. To address this question, Ijuin et al. (2008) administered both tests to a group of patients and compared the results. The following data represent results similar to those obtained in the study.    7-Minute Screen Cognitive Series 3 11 8 19 10 22 8 20 4 14 7 13 4 9 5 20 14 25 Which statistical test would you select: Answer    H0: Answer H1: Answer What is the coefficient that indicates the strength of the relationship? Answer =Answer What is the standard error? Answer What is the appropriate 95% CI?  [ Answer , Answer ] What is the d-effect size? Answer What is the t-observed? Answer What is the actual p-value? Answer THREE decimal places…

Explain the concept of Quasi-Experiments?

Early life corresponds to the first bacterial colonization of the digestive tract, creating a microbiome thought to play an important role in human development. What might be the effect of early exposure to antibiotics on children's development? One study followed 11,532 full-term babies all born in the county of Avon, United Kingdom, during 1991 and 1992. Exposures to antibiotics during infancy were recorded, along with measures of body mass at regular intervals over several years. The researchers found that antibiotic exposure during the first six months of life was associated with increased body mass later in childhood.