Chapter 18 Study Design and Data Handling

Question 1

What is a hypothesis?

a. Description of the study variables
b. Review of alternative research methods
c. Prediction of the results of the study
d. Statistical calculation of the probability of success

Answer 1

c. Prediction of the results of the study

Question 2

When is the study design of a research protocol developed?

a. Before a study is done
b. When the study is started
c. Midway during the study
d. At the end of the study

Answer 2

. a. Before a study is done

Question 3

How is “variable” defined in the biomedical research field?

a. It refers to something that cannot be measured accurately.
b. It represents anything that is not controlled during the study.
c. It refers to what is being measured during the study.
d. It represents anything that can affect the results of a study.

Answer 3

d. It represents anything that can affect the results of a study.

Question 4

In a study on whether a food treat helps rats to learn a specific behavior more quickly, what is the
minimum number of groups that you would need?
a. 1
b. 2
c. 3
d. 4

Answer 4

b. 2

Question 5

How is the term randomization defined in biomedical research?

a. It is a method of collecting data.
b. It is a method used to predict the study results.
c. It is a method of distributing animals among the study groups to avoid bias.
d. It is a method used in applied statistics.

Answer 5

c. It is a method of distributing animals among the study groups to avoid bias

Question 6

What does it mean when experimental results show a significant difference at a p-value of 0.05?
a. There is a 5% probability that the control group results differed significantly from the
treatment group.
b. There is a 95% probability that the difference is due to the treatment.
c. There is a 95% chance that he alternative hypothesis is false.
d. There is a 5% chance that the difference was due to the treatment.

Answer 6

b. There is a 95% probability that the difference is real.

Question 7

What is the confidence level?

a. Index of certainty
b. Index of value dispersion among groups
c. Index of chance occurrence
d. Index of randomization

Answer 7

a. Index of certainty

Question 8

What is the mean of a group of measurements?

a. The average of all the measurements
b. An indication of how similar all the measurements are
c. The variable that is being measured
d. The sum of all the measurements

Answer 8

a. The mathematical average of all the measurements

Question 9

In statistical analysis, what term describes how spread out the individual measurements are from
one another?
a. Confidence level
b. p-value
c. Standard deviation
d. Statistical significance

Answer 9

c. Standard deviation

Question 10

. You are trying to determine the survival rate of 1,000 zebrafish per tank over 4 weeks when housed
at a water temperature of either 25.5 °C or 27 °C on the survival rate of zebrafish in a tank that
contains 1,000 fish. What is the independent variable?
a. The temperature of the water in the tank
b. The total number of fish in the tank at the beginning of the experiment
c. The number of fish remaining at the end of the experiment
d. The number of times the tank is cleaned during the 4 weeks of the experiment

Answer 10

a. The temperature of the water in the tank

Question 11

If the p-value is set at 0.05, what is the confidence level?

a. 0.05
b. 0.50
c. 0.95
d. 1.00

Answer 11

c. 0.95

Question 12

A graph of data in a normal distribution is also known by what other term?

a. Bell-shaped curve
b. Dependent distribution
c. Independent variable
d. Experimental variation

Answer 12

a. Bell-shaped curve

Question 13

It is important to carefully follow the experimental design to avoid introducing unwanted
___________ that could affect the experimental results.
a. measurements
b. levels
c. variables
d. p-values

Answer 13

c. variables

Question 14

Which situation accurately describes a false positive result?
a. The treatment is found to have an effect on a sample group but not on the larger population.
b. The treatment is found to have no effect on a sample group although it would have a real effect
on the wider population.
c. The treatment causes no difference between the means of a measured variable in the treatment
and control groups.
d. Nonexperimental variation caused the difference between the treatment and control groups.

Answer 14

a. The treatment is found to have an effect on a sample group but not on the larger population

Question 15

Which term is defined as the chance that any real effect of treatment on the variable measured will
be detected by the study?
a. Power
b. Bias
c. Null hypothesis
d. Reproducibility

Answer 15

a. Power

Question 16

Which term is defined as the probability that the observed difference happened by chance alone
rather than due to the experimental treatment?
a. p-value
b. Confidence level
c. Reproducibility
d. Power

Answer 16

a. p-value

Question 17

Which value refers to the condition of the null hypothesis?

a. p-value
b. confidence level
c. bias
d. power

Answer 17

a. p-value

Question 18

Which term is defined as test subjects used to represent the whole population?

a. Sample
b. Control group
c. Treatment group
d. Dependent variable

Answer 18

a. Sample

Question 19

Statistics

Answer 19

the science that deals with the collection, classification, analysis, and interpretation of data by the use of probability theory.

Question 20

What are two ways bias can lead to erroneous data?

Answer 20

by producing false positives or false negatives

Question 21

experimental hypothesis

Answer 21

is a prediction of the results of a study; it is a statement of the answer the investigator expects to find to the research question.

Question 22

null hypothesis

Answer 22

states that there is no difference between the means of the two groups; that is, the treatment has no effect on the dependent variable

Question 23

alternative hypothesis

Answer 23

states the opposite of the null hypothesis

Question 24

variable

Answer 24

anything that can potentially affect the results of the study.

Question 25

independent variable

Answer 25

the variable that is manipulated by the investigator.

Question 26

dependent variable

Answer 26

the variable that is measured during the study.

Question 27

treatment group

Answer 27

the group that receives the treatment

Question 28

control group

Answer 28

a group of animals that is as similar as possible to the treatment group, but that does not receive the treatment.

Question 29

confidence level

Answer 29

is an index of certainty. It represents the probability that any difference found between the treatment and the control group data is due to the experimental treatment and not to the normal variation that exists among the animals.

Question 30

p-value

Answer 30

the probability that the observed difference happened by chance alone rather than due to the experimental treatment.
refers to the condition of the null hypothesis.
The confidence level and the p-value add up to 100%. If the confidence level is set at 0.95, then the p-value is 0.05.