Chapter 18 Study Design and Data Handling Flashcards
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
c. Prediction of the results of the study
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
. a. Before a study is done
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.
d. It represents anything that can affect the results of a study.
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
b. 2
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.
c. It is a method of distributing animals among the study groups to avoid bias
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.
b. There is a 95% probability that the difference is real.
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
a. Index of certainty
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
a. The mathematical average of all the measurements
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
c. Standard deviation
. 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
a. The temperature of the water in the tank
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
c. 0.95
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
a. Bell-shaped curve
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
c. variables
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.
a. The treatment is found to have an effect on a sample group but not on the larger population
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
a. Power
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
a. p-value
Which value refers to the condition of the null hypothesis?
a. p-value
b. confidence level
c. bias
d. power
a. p-value
Which term is defined as test subjects used to represent the whole population?
a. Sample
b. Control group
c. Treatment group
d. Dependent variable
a. Sample
Statistics
the science that deals with the collection, classification, analysis, and interpretation of data by the use of probability theory.
What are two ways bias can lead to erroneous data?
by producing false positives or false negatives
experimental hypothesis
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.
null hypothesis
states that there is no difference between the means of the two groups; that is, the treatment has no effect on the dependent variable
alternative hypothesis
states the opposite of the null hypothesis
variable
anything that can potentially affect the results of the study.
independent variable
the variable that is manipulated by the investigator.
dependent variable
the variable that is measured during the study.
treatment group
the group that receives the treatment
control group
a group of animals that is as similar as possible to the treatment group, but that does not receive the treatment.
confidence level
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.
p-value
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.
