Category: Uncategorized

Researchers who wanted to see if drinking grape juice could help people lower their blood pressure got 120 non-smokers to volunteer for a study. They measured each person’s blood pressure and then randomly divided the subjects into two groups. One group drank a glass of grape juice every day while the other did not. After sixty days the researchers measured everyone’s blood pressure again. They reported that differences in changes in blood pressure between the groups were not statistically significant.a. Was this an experiment or an observational study? Explain briefly.b. Briefly explain what “not statistically significant” means in this context.c. Briefly explain why the researchers randomly assigned the subjects to the groups.d. Since everyone’s blood pressure was measured at the beginning and at the end of the study, the researchers could have simply looked at the grape juice drinkers to see if their blood pressure changed. Briefly explain why the researchers bothered to include the control group.e. Briefly explain why the researchers studied only non-smokers.f. Other researchers now plan to replicate this study using both smokers and non-smokers. Briefly describe the design strategy you think they should use. 

A polling organization is investigating public opinion about cloning. They phone a random sample of 1200 adults, asking each person one of these questions (randomly chosen):A: “Do you favor allowing doctors to use cloned cells in attempts to find cures for such terrible diseases as Alzheimer’s, diabetes, and Parkinson’s?”B: “Should research scientists be allowed to use cloned human embryos in their experiments?”Which question do you expect will elicit greater support for cloning? Explain. What kind of bias is this? 

Which statement about bias is true?I. Bias results from random variation and will always be present.II. Bias results from a sampling method likely to produce samples that do not represent the population.III. Bias is usually reduced when sample size is larger. 

Height and weight Suppose that both height and weight of adult men can be described with Normal models, and that the correlation between these variables is 0.65. If a man’s height places him at the 60th percentile, at what percentile would you expect his weight to be? 

Which process produces alcohol or lactate? 

Does donating blood lower cholesterol levels? 50 volunteers have a cholesterol test, then donate blood, and then have another cholesterol test. Which aspect of experimental design is present? 

The membrane protein (enzyme) that transforms ADP + P to  ATP as H+ flows down a gradient from the intermembrane space into the matrix is:

In a covalent bond: 

A spherical shaped bacterial cell is considered:

A headline in the New York Times announced “Research shows running can alter one’s moods”. The article reported that researchers gave a Personality Assessment Test to 231 males who run at least 20 miles a week, and found “statistically significant personality differences between the runners and the male population as a whole.” Do you think the headline was appropriate? Explain.