Critical Evaluation Flashcards
What are the two types of variation?
Discrete
Continuous
Describe ‘Normal distribution’
- Bell curve
- Most common distribution in nature
- Symmetrical
Give an example of a pattern that shows normal distribution
Height of humans
What are the two types of skewed distribution?
Negative and Positive
Describe ‘Skewed Distribution’
- Can be negative or positive
- Mean is not the most common value
- Most common value is not central
Give an example of skewed distribution
Number of children in household
What should a representative sample have?
Same mean and degree of variation about the mean as the population as a whole
What should be considered when assessing precision and accuracy?
- Mean of replicated measurements
- Variation in these replicated measurements
- Number of samples tested
- How regularly measurement equipment requires calibration
What is a confidence interval?
Statistical estimate of range of values within a certain percentage of the total population would be found
What is a statistically significant result?
One in which the difference between groups is unlikely to be due to chance alone
What p value shows the results are statistically significant?
0.05
What are the two types of control groups?
Negative and Positive
What does a negative control group do?
Provide data for what happens in the absence of a treatment
What controls should be used to test for false positive results?
Negative
What do positive control groups prove?
The experimental design can detect a change in the dependent variable when one occurs
What gives an indication of the strength of the correlation?
Dispersion of the points about the line
In what circumstances can correlation demonstrate causation?
When all the confounding variables are controlled
Where are in vitro studies carried out?
Lab
Describe ‘In Vivo’ Studies
‘Within the living’
Studies involving living organisms
Give two advantages and disadvantages of in vivo studies
Advantages: - Provides data for effects in whole organisms - Allows study of complex interactions Disadvantages: - Expensive and time consuming - Difficult to prove causation
Give two advantages of in vitro studies
- Simpler and less expensive
- Easier to control confounding variables
- Interpretation of results is simpler
Give two disadvantages of in vitro studies
- Difficult to extrapolate results to whole organisms
- Difficult to model complex interactions
