Bio 180 Exam 1 Questions and Answers
(Top Grade Assured) 2026 Update
What is the difference between a theory and a hypothesis? -
Correct Answers ✅Only scale--theories deal with "big
ideas" that impact large parts of the physical or natural
world; hypotheses are more focused or narrower in scope.
What is the difference between a hypothesis and a
prediction? - Correct Answers ✅A hypothesis is an idea--a
testable explanation; a prediction is something that follows
from a hypothesis and that you can measure
example of prediction - Correct Answers ✅If you boil
nutrient broth and place it in an air-tight flask, no cells will
appear in the broth
What was important about the experimental design for
Pasteur's flask experiment? - Correct Answers ✅He
compared results from two experimental setups which
differed only in the type of flask in which the nutrient broth
was placed
How do biologists test their ideas about the natural world? -
Correct Answers ✅Scientists make predictions based on
hypotheses they have developed, and then design
experiments or other types of studies to test those
predictions
,Bio 180 Exam 1 Questions and Answers
(Top Grade Assured) 2026 Update
Why is it important to perform multiple trials in an
experiment -- meaning that you include many test individuals
or samples? - Correct Answers ✅To make it more likely that
the results are not due to a few unusual individuals or
circumstances
The remaining questions refer to this situation: Researchers
do an experiment to test the hypothesis that Douglas fir trees
put more resources into reproduction when they are infected
with a fungus that causes a fatal disease. They establish
study plots in a group of 50-year-old Douglas fir where the
disease is not present. At random, they inject half the trees
with the disease-causing fungus. Then they measure how
many cones and seeds are produced by infected versus
uninfected trees.
What prediction follows from the hypothesis? - Correct
Answers ✅On average, the infected trees will produce more
seeds than uninfected trees
Which treatment would be considered the control? - Correct
Answers ✅The uninfected trees
Why is it important to do the experiment in the same group
of same-aged trees? - Correct Answers ✅To eliminate the
possibility that the results are due to differences in age, soil,
moisture, or other relevant variables
, Bio 180 Exam 1 Questions and Answers
(Top Grade Assured) 2026 Update
Why is it important that they assigned trees to the infected
versus uninfected groups at random? - Correct Answers
✅If assignment were not done at random, the result could be
do to something other than the difference in infection
If the hypothesis is wrong, and being infected with the fungus
has no impact at all on reproduction, what should they
observe? - Correct Answers ✅There will be no difference in
the number of seeds produced by infected versus uninfected
seeds
A friend says that this experimental design would be better if
the researchers had injected the control group trees with a
solution that was identical to that used in the experimental
group, but without the fungus. Do you agree? - Correct
Answers ✅Yes. As is, it would be reasonable for a critic to
claim that seed production changed because of the injection
itself, not the presence of the fungus.
What does the p in "p-value" represent? - Correct Answers
✅Probability (of getting the observed result, just by chance)
Suppose we run a statistical test, and learn that p = 0.01.
What does this mean? - Correct Answers ✅There is a 1 in
100 chance of observing a difference between treatment
groups this extreme if the null hypothesis is correct.
(Top Grade Assured) 2026 Update
What is the difference between a theory and a hypothesis? -
Correct Answers ✅Only scale--theories deal with "big
ideas" that impact large parts of the physical or natural
world; hypotheses are more focused or narrower in scope.
What is the difference between a hypothesis and a
prediction? - Correct Answers ✅A hypothesis is an idea--a
testable explanation; a prediction is something that follows
from a hypothesis and that you can measure
example of prediction - Correct Answers ✅If you boil
nutrient broth and place it in an air-tight flask, no cells will
appear in the broth
What was important about the experimental design for
Pasteur's flask experiment? - Correct Answers ✅He
compared results from two experimental setups which
differed only in the type of flask in which the nutrient broth
was placed
How do biologists test their ideas about the natural world? -
Correct Answers ✅Scientists make predictions based on
hypotheses they have developed, and then design
experiments or other types of studies to test those
predictions
,Bio 180 Exam 1 Questions and Answers
(Top Grade Assured) 2026 Update
Why is it important to perform multiple trials in an
experiment -- meaning that you include many test individuals
or samples? - Correct Answers ✅To make it more likely that
the results are not due to a few unusual individuals or
circumstances
The remaining questions refer to this situation: Researchers
do an experiment to test the hypothesis that Douglas fir trees
put more resources into reproduction when they are infected
with a fungus that causes a fatal disease. They establish
study plots in a group of 50-year-old Douglas fir where the
disease is not present. At random, they inject half the trees
with the disease-causing fungus. Then they measure how
many cones and seeds are produced by infected versus
uninfected trees.
What prediction follows from the hypothesis? - Correct
Answers ✅On average, the infected trees will produce more
seeds than uninfected trees
Which treatment would be considered the control? - Correct
Answers ✅The uninfected trees
Why is it important to do the experiment in the same group
of same-aged trees? - Correct Answers ✅To eliminate the
possibility that the results are due to differences in age, soil,
moisture, or other relevant variables
, Bio 180 Exam 1 Questions and Answers
(Top Grade Assured) 2026 Update
Why is it important that they assigned trees to the infected
versus uninfected groups at random? - Correct Answers
✅If assignment were not done at random, the result could be
do to something other than the difference in infection
If the hypothesis is wrong, and being infected with the fungus
has no impact at all on reproduction, what should they
observe? - Correct Answers ✅There will be no difference in
the number of seeds produced by infected versus uninfected
seeds
A friend says that this experimental design would be better if
the researchers had injected the control group trees with a
solution that was identical to that used in the experimental
group, but without the fungus. Do you agree? - Correct
Answers ✅Yes. As is, it would be reasonable for a critic to
claim that seed production changed because of the injection
itself, not the presence of the fungus.
What does the p in "p-value" represent? - Correct Answers
✅Probability (of getting the observed result, just by chance)
Suppose we run a statistical test, and learn that p = 0.01.
What does this mean? - Correct Answers ✅There is a 1 in
100 chance of observing a difference between treatment
groups this extreme if the null hypothesis is correct.
