Answers & Feedback for TOSLS Questions

Question 1

1. Incorrect choice. Sea level can vary from year to year. To assess how sea level changes over time, scientists look at more than just one year’s worth of data. They interpret how the sea level has changed across decades, centuries, even millennia. 
2. Correct choice. This experiment examines how a single gene affects mouse reproduction.
3. Incorrect choice. A poll of public opinion cannot be used to test a scientific claim or hypothesis. Unless the hypothesis is that “a substantial portion of Americans think that humans once hunted dinosaur.”
4. Incorrect choice. Climate change is something that occurs over long periods of time. Measurements from a single season or just one year can’t be used to prove that climate change is (or is not) taking place. Such data needs to be considered in the context of how measurements of temperature or precipitation are changing over tens or hundreds or thousands of years.

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Question 4

1. Incorrect choice. The unequal distribution of females in the two groups could skew or “confound” the results of this experiment.
2. Incorrect choice. It would be questionable to make any kind of general statement about the religious beliefs of all American university students based on data obtained from a single, private university in the South. Here, the geographic selection could prove a confounding factor. 
3. Correct. This experiment is designed to minimize some of the factors that could make the results difficult to interpret: differences in daily exercise or participants’ starting weight. 
4. Incorrect choice. The fact that the control group and the experimental group were examined at different times of year, when tree growth can differ, would be a confounding factor in this experiment.

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Question 5

1. Incorrect choice. Cherry picking the data that supports a particular conclusion, while ignoring contradictory data, is not a scientifically valid course of action.
2. Incorrect choice. Although journalists are trained to represent both sides of a story, theories that have been repeatedly disproven should never be given equal weight. 
3. Incorrect choice. Making decisions about the public health based on pressure from an industry with a financial stake in the outcome is not a scientifically valid course of action.
4. Correct. Understanding the long-term effects of a drug that will likely need to be administered for decades is necessary to ensure that the treatment will be safe.

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Question 9

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Question 11

1. Incorrect choice. This evidence does not offer any insights into whether the participants drank more diet soda.
2. Correct. This study is similar in design to a clinical trial that tests the effectiveness of different doses of a drug.
3. Incorrect choice. This evidence pertains to an ingredient that might be found in any cola—diet or otherwise. 
4. Incorrect choice. This evidence introduces a confounding factor, as smoking itself likely leads to increases in vascular events. 

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Question 12

1.  Incorrect choice. The use of the phrase “A recent study…” suggests that this excerpt was not actually part of the study report itself. Had the scientists written about their results, they would have said “We find that…” or “Our study shows that…”
2. Incorrect choice. A review article would have put the results into context based on other similar studies. This excerpt only describes a single study.
3. Correct. The excerpt refers to the researchers by name and describes one particular study.
4. Incorrect choice. Take another look at the excerpt and consider how it presents the study’s authors and whether it puts the study in a broader context.

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Question 13

1. Incorrect choice. While it is true that New Yorkers are not necessarily representative of all Americans, also consider whether other answers might be valid.
2. Incorrect choice. It is true that although the researchers did examine a few confounding variables (smoking, high blood pressure), they could not rule out all possible alternative explanations. However, are any of the other answers provided here also true?
3. Incorrect choice. It is true that this study does not represent a blinded, randomized trial. However, is this the only reason the researcher might hesitate to warn people away from diet sodas?
4. Correct.

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Question 14

1. Incorrect choice. The sample size is large enough to produce some statistically valid conclusions.
2. Incorrect choice. The excerpt states that the researcher randomly surveyed the study participants.
3. Correct. Although it might not eliminate all confounding variables, the results would be stronger if the study were a blinded, randomized trial.
4. Incorrect choice. The study actually does have some strengths!

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Question 17

1. Incorrect choice. The way the data is formatted or presented does not guarantee it is correct. Anyone can put things in a table! And many valid scientific papers have no graphs or tables at all.
2. Correct. Peer review is a cornerstone of the scientific process.
3. Incorrect choice. Skillful writing does not make a study trustworthy—although it does make the paper easier to read and understand! 
4. Incorrect choice. The publisher does not guarantee the validity of a study’s results.

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Question 27