BIO 1101 Chapter 1
In this illustration, different sample sizes influence the results of the experiment. However, only male rats should have been studied, because they more accurately represent the population of humans who use cells phones.
False; both sexes should always be presented whenever possible.
Which of these is NOT an example of recall bias?
A patient with brain cancer may be more likely to recall childhood memories.
A newspaper has recently received several complaints regarding the accuracy of its reports on scientific studies. As a result, the newspaper's editors have posted an ad seeking a new science journalist. What steps are NOT important for the newspaper to take to ensure that the new science journalist can produce accurate articles?
Ensure that the new science journalist has an advanced degree in a scientific discipline and regularly acts as a peer reviewer for scientific journals.
What did the researchers conclude from the experiment about how cell phone radiation affects the incidence of cancer
Cell phone radiation increased the likelihood of certain cancers in male rats
In the studies of cell phone use and cancer discussed, the independent variable is _____ and the dependent variable is _____ .
Cell phone use; cancer rates
Which statement is a pitfall for making decisions from a single epidemiological study?
Complexity of a disease makes it unlikely that every variable can be controlled for, small sample sizes can influence the accuracy of results, and the specific population in the study may not be representative of the general population.
Which statement describes a correlation between two Variables?
Correlated variables are interdependent; as one varies so does the other in a predictable fashion
Based on a thorough literature review, a researcher has found studies supporting correlations between drug use and neurological diseases, weight gain, and brain cancer. Based on these correlations, what can he conclude regarding drug use?
Drug use may cause neurological diseases, weight gain, and brain cancer.
Which statements describe the relationship between correlation and causation? Select Two answers that are correct
Either variable might be the cause, or both variables might be influenced by a third unknown variable Correlation alone is not sufficient evidence to attribute causation
When scientists carry out an experiment, they are testing a _____.
Hypothesis
Why is sample size important?
Larger sample size increases the likelihood that the results of a study are not due to random chance.
From what you have read in this chapter, would you advise family and friends to limit the amount of time they spend talking on their cell phones?
No, because the peer-reviewed study cited multiple concerns, including that it did not distinguish specific types of cancers and no dose-response relationship was consistently found.
Can an epidemiologist who finds a correlation between the use of tanning beds and melanoma (an aggressive form of skin cancer) in college-age women conclude that tanning beds cause skin cancer
No, correlation is not proof of causation.
This is an illustration demonstrating the influence of different sample sizes. Is the smallest sample size an accurate depiction of the results?
No, the smallest sample size produced inconsistent results.
A group of friends are watching a televised debate on evolution. One of the participants repeatedly states that evolution is a "scientific theory," and as such is unsupported by any evidence. What is wrong with this statement?
Nothing. This statement is correct. Scientific theories are rigorously supported by numerous studies, and are hypotheses that (to date) have never been disproved.
Melanoma rates are higher in areas of the United States with a high number of sunny days each year. Melanoma rates have been observed to decrease in some countries in response to public health campaigns that promote regular use of sunscreen. Other types of skin cancer, which are similar to melanoma, are linked to UV exposure. Based on this information, what is the MOST comprehensive hypothesis that can be generated?
People who use sunscreen have lower rates of skin cancer in general.
Use the following information for the question below:You conduct a clinical trial to test whether a new drug relieves the symptoms of arthritis better than a placebo. You have four groups of participants, all of whom have moderately painful arthritis (rated 7 on a scale of 1 to 10). Each group receives a daily pill as follows: group 1-placebo; group 2-15 mg; group 3-25 mg; group 4-50 mg. At the end of 2 weeks, participants in each group are asked to rate their pain on a scale of 1 to 10. Based on the process of science, what would be your next step?
Run a statistical analysis on the data collected
You are listening to a news report that claims a new study has found convincing evidence that a particular weight-loss product is much more effective than diet and exercise Which statement would be an example of scientifically "convincing" evidence in this case?
Statistical tests showed significantly more weight loss in the participants who used the weight-loss product than those who relied on diet and exercise.
Which example describes the set up of a controlled experiment
Ten subjects receive a new drug and another ten subjects receive a sugar pill
What characteristics does a scientific hypothesis have? Select two answers
The hypothesis is something that can be tested The hypothesis could be proven false
Using the same independent and dependent variables as in the first experiment, researchers could extend the studies to test which of the following hypotheses? Select the TWO answers that are correct.
The incidence of cancer increases with increased levels of cell phone radiation Low intensity, Long duration exposure to radiation has a greater influence on the incidence of cancer that high intensity, short duration exposure
How can statistics be used in a scientific study?
They determine whether observed differences are significant or a result of chance.
A group of friends are reading an article in the newspaper regarding BPA (a chemical found in certain plastics), and whether this chemical causes cancer. At the end of the article, the journalist writes, "Given that three independent studies have provided evidence that BPA is a carcinogen, this hypothesis is true and no more research is necessary. The public should avoid BPA-containing products at all costs." Is there anything wrong with this statement?
Yes. No hypothesis can ever be shown to be definitively "true." The three studies that the journalist notes only provide evidence that BPA could cause cancer; more studies are likely necessary.
A statistically significant result from a scientific study is indicative of:
a nonrandom result.
Which of the following is most likely to provide the most scientifically rigorous and accurate information
a randomized clinical trail with 15,000 subjects
In a study designed to test whether cell phone radiation increases the incidence of brain cancer, which of these is the experimental group?
animals treated with cell phone radiation
Researchers are hoping to determine the efficacy of a new drug that (supposedly) reduces cholesterol in patients. To this end, they carry out a randomized clinical trial, where one group of subjects receives the cholesterol drug and the other group receives a placebo. Researchers then periodically measure the cholesterol levels in individuals from both of these groups. In this scenario, _____ would be considered the dependent variable.
cholesterol levels in subjects
Of the following, which is the first step in the scientific process?
developing questions based on observations
A close friend has joined a clinical trial. When you ask her about the types of treatment she might be given, she tells you that neither she nor the doctor running the trial will know until the process has been completed. What type of trial has she joined?
double-blind
A study was conducted to investigate if the use of SPF30 sunscreen lotion is a more effective skin cancer prevention measure than SPF15 sunscreen lotion. The study involved comparing a group of roofers who had developed skin cancer to a group of roofers without skin cancer and assessing their use of sunscreen lotions. This is an example of a(n):
epidemiological case-control study.
Statistically significant results are more likely to be obtained from experiments that:
have a large sample size in both groups.
This figure shows data from an experiment that examined the contribution of cell phone use to the development of brain cancer. What is the dependent variable?
incidence of brain cancer
An experiment is being conducted in which male and female rats are randomly placed into two equivalent groups. One group receives periodic radiation from a cell phone 9 hours per day for 2 years. Both groups are monitored for potential cancer development. At the end of the study, the male rats receiving cell phone radiation have a greater incidence of cancer compared to the other group. In this study, which factor is the independent variable?
periodic cell phone radiation
Anna is majoring in public health. She is designing an epidemiological study to examine the relationship between alcohol consumption and academic performance at her university. In addition to ensuring that she has a large enough sample size, what strategy should she take to make sure her conclusions are accurate?
randomly survey a group of participants that are representative of the general student body
Which phrase is NOT a factor influencing the misrepresentation of research data in the media?
scientists intentionally obscuring research data to make it difficult for non-scientists to understand their results
In a controlled experiment, which group receives the placebo?
the control group
Use the following information for the question below:You conduct a clinical trial to test whether a new drug relieves the symptoms of arthritis better than a placebo. You have four groups of participants, all of whom have moderately painful arthritis (rated 7 on a scale of 1 to 10). Each group receives a daily pill as follows: group 1-placebo; group 2-15 mg; group 3-25 mg; group 4-50 mg. At the end of 2 weeks, participants in each group are asked to rate their pain on a scale of 1 to 10. Based on the process of science, what is the experimental variable
the drug itself
When is a hypothesis considered scientific?
when it can be tested and refutable